fabric conditioning for more gentle shredding
TRANSCRIPT
Visiting address: Skaraborgsvägen 3 Postal address: 501 90 Borås Website: www.hb.se/ths
Thesis for the Degree of Master in Science
with a major in Textile Engineering
The Swedish School of Textiles
2018-06-08 Report no. 2018.14.03
FABRIC CONDITIONING FOR MORE
GENTLE SHREDDING
- Pre-treatment for mechanical recycling of cotton and polyester
Therese Sjöblom
i
ABSTRACT There is a growing need for fibres with increasing population. One way to
solve this is to recycle the fibres from textile waste. In mechanical recycling
by shredding the textiles are shredded back to fibrous form. The biggest
problem with shredding is that it is a harsh process that reduces the fibre
length and damages the fibre.
To make the shredding process more gentle and preserve more of the fibre
length, pre-treatment that lowers the friction between the fibres have been
investigated. Polyethene glycol 4000 (PEG 4000) is an environmentally
friendly chemical that could be used to lower the friction of cotton and
polyester, the two most used textile fibres. Another treatment evaluated is
glycerol. The treatment should not affect further processing of the fibres.
For evaluating the treatment, a test of the interfibre friction was performed
on carded webs and fabrics that were untreated and treated. Prior to
shredding four samples were made of fabrics of cotton, polyester and
polycotton. From each fabric, one was left untreated, and one was treated
with a low concentration of PEG 4000. The concentration of PEG 4000 was
chosen from the test on fibres. Also from each fabric, two treatments that
were not prepared by the author; one with a high concentration of PEG 4000
and the other with glycerol. All 12 samples were shredded back to fibres.
The shredded material was analysed, and the fibre length was measured.
The reclaimed fibres from the shredded material were also tried to be
processed into yarns.
The main result was that it was possible to rotor spin yarn of 100%
reclaimed fibres from cotton and polyester treated with PEG 4000, which
means that the treatment did not interfere with the spinnability of the
reclaimed fibres. Untreated cotton was also spinnable, but untreated
polyester was not possible to card. The cotton and polyester treated with
glycerol were possible to carded and made into a sliver but not spinnable.
The reclaimed fibres from the polycotton fabric were not possible to card or
process further. This result correlates with the analyses of the shredded
material and the fibre length measurement. The best results were for
polyester treated with 0.71 w% PEG 4000 that had 121% longer mean fibre
length than untreated polyester. The best result for cotton was treated with
0.29 w% PEG 4000.
Keywords: Mechanical recycling, Reclaimed fibres, Shredding, Fibre
length, Ring spinning, Rotor spinning, Cotton, Polyester, Sustainable
development.
iii
POPULAR ABSTRACT Polyester and cotton are the two most used textile fibres in the world. In
mechanical recycling, the textiles are shredded back into a fibrous form. The
recycled fibres can then be used for new applications. The main drawback
of this method is that the fibres get much shorter and cannot be processed
into products with higher quality and are therefore downcycled into products
such as isolation or nonwovens. To be able to produce yarns from the
recycled fibres the recycled fibres are often blended with new fibres to get
yarn of higher quality.
To make the shredding process gentler and preserve more of the fibre
length, two pre-treatments, polyethene glycol 4000 (PEG 4000) and
glycerol, both environmentally friendly chemicals, have been tested for their
ability to lower the friction between the fibres. Three fabrics have been
treated; plain weave of cotton, polyester and a blend of cotton and polyester.
The main result was that it was possible to rotor spin yarn of 100%
mechanical recycled fibres from cotton and polyester treated with PEG
4000, which means that the treatment did not interfere with the spinning
process. Also, recycled fibres from the untreated recycled cotton were
possible to spin into yarn. The recycled fibres from the blend of cotton and
polyester were not possible to spin yarn from. Neither of the recycled fibres
from the fabrics treated with glycerol was possible to produce a yarn out of.
The fibre length of the recycled fibres from all fabrics treated with PEG
4000 was longer compared to untreated fibres. The recycled polyester fibres
were 120 % longer than untreated recycled polyester fabrics, and the
recycled cotton fibres almost 50 % longer compared with untreated recycled
cotton fibres
v
ACKNOWLEDGEMENT This thesis is for the degree of Master in Science with a major in Textile
Engineering, and the thesis work is 30 credits. This project was initiated by
Nawar Kadi and Anders Persson. Thank you both for all help and
supervision. Also thanks to the wonderful technicians at the Swedish School
of Textiles. I want to thank my classmates for this time together in the
master programme.
I wish to thank Swerea IVF for letting me use your equipment for shredding
and rotor spinning. Thanks to Lisa Schwarz Bour, Louise Holgersson,
Rebecca Landin and Desiré Rex at Swerea IVF. Without your help, this
work would not have been possible.
A special thanks to Anders Berntsson from Textilmusset in Borås for all
your help and expertise.
Thanks to my friends Johanna and Anna for proofreading.
I wish to dedicate this work to my mother for leading the way. Thank you
for always helping and supporting me.
And finally, thanks to Albin for all help, love and support during this
process.
Therese Sjöblom
June 2018
vii
TABLE OF CONTENT Abstract ........................................................................................................... i
Popular abstract ............................................................................................ iii
Acknowledgement .......................................................................................... v
Introduction ............................................................................................. 1 1.
Background ...................................................................................... 1 1.1.
Problem description ......................................................................... 2 1.2.
Aim .................................................................................................. 3 1.3.
Research questions ........................................................................... 3 1.4.
Hypothesis ....................................................................................... 3 1.5.
Limitations ....................................................................................... 3 1.6.
Literature review ..................................................................................... 4 2.
Textile recycling .............................................................................. 4 2.1.
Mechanical recycling ....................................................................... 5 2.2.
Chemical recycling .......................................................................... 8 2.3.
From fibre to yarn ............................................................................ 8 2.4.
Yarn spinning ........................................................................... 9 2.4.1.
Rotor spinning ................................................................. 10 2.4.1.1.
Fibre length measurement .............................................................. 11 2.5.
Friction in textiles .......................................................................... 12 2.6.
Interfibre friction ............................................................. 13 2.6.1.1.
Yarn pull-out test ............................................................ 13 2.6.1.2.
Materials ........................................................................................ 14 2.7.
Cotton ..................................................................................... 14 2.7.1.
Polyester (PET) ...................................................................... 14 2.7.2.
Polyethylene Glycol (PEG) .................................................... 14 2.7.3.
Glycerol .................................................................................. 15 2.7.4.
Materials ................................................................................................ 16 3.
Methods ................................................................................................. 18 4.
Pre-study ........................................................................................ 18 4.1.
Fibre opening .......................................................................... 19 4.1.1.
Fibre treatment ....................................................................... 19 4.1.2.
Carding ................................................................................... 19 4.1.3.
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Novel method for tensile testing of carded webs ................... 20 4.1.4.
Raman spectroscopy .............................................................. 20 4.1.5.
Main study ..................................................................................... 21 4.2.
Fabric treatment, analyses and shredding .............................. 21 4.2.1.
Treatment of fabrics ....................................................... 21 4.2.1.1.
Analyses of the fabrics ................................................... 23 4.2.1.2.
Shredding and cutting ..................................................... 25 4.2.1.3.
Shredded materials ................................................................. 26 4.2.2.
Fibre length measurement .............................................. 27 4.2.2.1.
Visual analysis of shredded material .............................. 28 4.2.2.2.
Carding ........................................................................... 28 4.2.2.3.
Sliver ............................................................................... 28 4.2.2.4.
Rotor spinning ................................................................ 29 4.2.2.5.
Linear density for rotor spun yarns ................................ 30 4.2.2.6.
Washing of rotor spun yarns ........................................... 30 4.2.2.7.
Tensile strength of yarns from rotor spinning ................ 30 4.2.2.8.
Visual analysis of yarn ................................................... 31 4.2.2.9.
Analysis of data and statistic ......................................................... 31 4.3.
Results .................................................................................................. 32 5.
Results from pre-study .................................................................. 32 5.1.
Results from the main study .......................................................... 34 5.2.
Fabric treatment, analyses and shredding .............................. 34 5.2.1.
Fabric preparation ........................................................... 34 5.2.1.1.
Analysis of fabric ........................................................... 34 5.2.1.2.
Tensile strength of yarns from fabrics ............................ 35 5.2.1.3.
Fibre length measurement of fibres from fabrics ........... 36 5.2.1.4.
Pull-out test ..................................................................... 36 5.2.1.5.
Shredded material: ................................................................. 38 5.2.2.
Analysis of shredded material ........................................ 39 5.2.2.1.
Fibre length measurement .............................................. 40 5.2.2.2.
Carding of shredded material ......................................... 42 5.2.2.3.
Sliver ............................................................................... 43 5.2.2.4.
Yarn production .............................................................. 44 5.2.2.5.
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Linear density of rotor spun yarn .................................... 46 5.2.2.6.
Tensile test of produced yarn .......................................... 47 5.2.2.7.
Visual analysis of the rotor spun yarns ........................... 48 5.2.2.8.
Discussion ............................................................................................. 49 6.
Conclusions ........................................................................................... 55 7.
Future research ............................................................................... 56 7.1.
References .................................................................................................... 58
1
INTRODUCTION 1.In 2015 the UN presented their Sustainable Development Goals. The 17
goals aim to end poverty, ensure prosperity for all and protect the planet.
Each goal has specific targets to reach until 2030. Goal 12 is responsible
consumption and production (UN 2018a). Two of the targets in Goal 17 is
to achieve sustainable and efficient use of the natural resources and to
reduce waste generation through prevention, reduction, reuse and recycling
(UN 2018b).
The global demand for fibres is estimated to be 250 million metric tons
(MT) in the year 2050 according to Re:textile (2018) which is a large
increase compared to the textile production worldwide today, which was
estimated to be 95.4 million MT 2016 (Textile Exchange 2017).
The textile industry is affecting the environment; it uses a lot of resources of
energy, chemicals, pesticides, petroleum and water (Gullingsrud 2017:
Fletcher 2008). The textile industry is the world second most polluting
industry after the oil industry (Gullingsrud 2017). Lifecycle assessments
show that over 56 % of a textile product’s climate impact comes from the
processes from fibres to the finished product (Re:textile 2018).
Polyester (PET) is the most used fibre in the world and cotton the secondly;
of the textile production worldwide was estimated that polyester was 41.5 m
MT and cotton 21 m MT (Textile Exchange 2017). According to the
Swedish Environmental Protection Agency, the textile consumption in
Sweden 2013 was 12.5 kg per person. From analyses of household garbage,
it was estimated that 8 kg per person and year is thrown away as trash
(Östlund et al. 2015). In 2015, an astonishing 73 % of all textiles worldwide
ended up in landfills or was incinerated. 12 % was cascade recycling also
called open-loop recycling. 12 % was cascade recycled also called open-
loop recycling. In comparison, the losses in production were also 12 %
(Statista 2017). Open-loop recycling is also called downcycling and means
that it is not recycled to a product of similar quality as the product before
recycling. Closed-loop recycling means it was recycled into a product with
similar quality and is also called upcycling (Hawley 2015). Only less than 1
% was closed loop recycled. (Statista 2017).
There is a need for the textile industry to change and become sustainable,
and developing the techniques of recycling could be one part of the solution.
BACKGROUND 1.1.Textiles for recycling can be categorised as pre-consumer waste or post-
consumer waste (Hawley 2006). Pre-consumer waste is industrial waste
2
from textile production, and post-consumer waste is garments or household
articles that are discarded because they are worn out or damaged, the size
does not fit anymore or simply gone out of fashion (Hawley 2006). Pre-
consumer waste is also referred to as post-industrial waste
Recycling is divided into mechanical recycling and chemical recycling
(Hawley 2006). Mechanical recycling could be referring to two things,
mechanical recycling by shredding textile material back to fibres and
mechanical recycling, by remelting plastic into new plastic, which is
sometimes called thermomechanical recycling. PET bottles could be
thermomechanical recycled into polyester textile fibres. Recycling bottles
into fibres are open-loop recycling. Polyester textiles however that are
recycled by chemical recycling were the polymer is broken down into
monomers and repolymerised. Chemical recycling and it is an example of
closed-loop recycling (Gullingsrud 2017).
Shredding is a process was textiles are torn back to fibrous form (Luiken &
Bouwhuis 2015). Shredding could also be called garnetting, grinding,
tearing or opening (Leonas 2017; Wang 2010; Fletcher 2014; Hawley
2009). In the shredder, the textile material is run through a series of high-
speed cylinders covered with spikes or wire that tears the textiles apart
(Gullingsrud 2017). Of the shredded fibres insulation, nonwovens, paddings
and new yarn (Östlund et al. 2015). The recycled mechanical fibres are also
called reclaimed fibres, are mixed with virgin fibres to get better quality
(Östlund et al. 2015; Gullingsrud 2017). During shredding 20 % of the
fibres are lost and during spinning and weaving additional 20 % is lost.
Further, all processing steps reduce the fibres strength. That is the reason
why the reclaimed fibres are mixed with virgin fibres. For yarn for denim
production, 20 % reclaimed fibres were mixed with 80 % virgin fibres.
This research builds on two previous theses about fibre recycling. Firstly,
Aronsson (2017) investigated the shredding of post-consumer waste.
Secondly, Namuga (2017) started to evaluate the possibility of lowering the
interfibre friction by different kinds of pre-treatment.
PROBLEM DESCRIPTION 1.2.The problem with mechanical recycling is the drop in fibre length; the
shredding process is harsh and tears the textiles apart into fibres.
The textiles were treated with conditioners in low concentration prior to
shredding to reduce the inter-fibre friction with the hope of a resulting lower
fibre length drop of the reclaimed fibres. First, the effects of the
conditioners, concentrations and suitable application procedure have been
evaluated by testing the interfibre friction of fibres in carded webs. In this
3
thesis, new fabrics have been shredded to estimate the impact of the
shredding process, but this research is done to facilitate the recycling of
textile waste into new textile applications. To be able to know more about
the impact of the shredding process on the fibres it is practical to have a
uniform material with known properties. New fabrics are therefore used in
this research due to that post-consumer textile could have damage related to
use and washing, which are additional factors that further could affect the
fibre length, and that would not be investigated in this thesis.
AIM 1.3.The aim is to accomplish gentler shredding that maintains fibre length and
cause less damage by the aid of conditioners that don’t affect spinnability.
RESEARCH QUESTIONS 1.4.● How will conditioners affect the interfibre friction?
● Can conditioners affect the fibre length drop during shredding?
● Can conditioners affect the neps count and amount of unopened
threads in the shredded material?
● How will the treatment work on cotton, polyester and their blends?
● Is the result of the fibres in carded webs applicable to the fibres in
woven constructions?
● Will the conditioners affect the subsequent processes in textile
manufacturing?
HYPOTHESIS 1.5.Conditioning of fabrics will make the shredding process gentler without
compromising spinnability.
LIMITATIONS 1.6.Only new fabric will be tested, all samples of the same material are taken
from the same roll of fabric, and all the fabric have a similar appearance.
The conditioner and their concentrations are the factors, not the fabrics. All
fabrics have been shredded in the same machine; it is not the machines for
shredding that is investigated.
4
LITERATURE REVIEW 2.In this part, textile recycling will be described further. The literature review
will cover methods such as yarn spinning, fibre length measurement and test
of friction and the materials that are used.
TEXTILE RECYCLING 2.1.As already mentioned, most of the textile waste ends up in landfills or is
insinuated for energy recovery. Textiles in landfills are contributing to
methane emissions and pollution of the groundwater (Fletcher 2008).
Textiles are nearly 100 % recyclable and should not end up in landfills
(Hawley 2009). Western lifestyle, with its over-consumption, is largely
contributing to landfill waste (Hawley 2009). In the USA, it is estimated that
in landfills textile constitute 5 % of the waste (Leonas 2017). According to
Larney & van Aardt (2010), which studied companies attitude towards
recycling in South Africa, landfills are still the most important practice for
disposal of textile waste. The authors point out that the low fees for landfills
could be one of the reasons for this.
For waste management, the European Commission (2016) Directive
2008/98/EC on waste, it is about basic concept and definitions of waste
management. This includes definitions of waste, recycling and recovery. It
also defines when waste is not waste but a secondary raw material and how
to distinguish between actual waste and by-products. Figure 1 is the waste
hierarchy which has disposal, landfill, as least desired option (European
Commission 2016). In addition to the pollution and greenhouse emission, it
is also a waste of resources. The European Commission estimate that the
materials send to landfill has an annual value of 5.25 billion euro. Better
than disposal is recovery, waste is often burned to recover the energy and
produce electricity, steam or the heating for buildings. The EU waste
directive aim to that waste should be recycled and used as raw material for
new products. After recycling is reuse, it has both environmental benefits
but also social and economical, it creates new jobs and provides more
affordable options than buying new (European Commission 2010). First in
the waste hierarchy is prevention (European Commission 2016). Good
waste management starts with prevention of waste (European Commission
2010).
5
Figure 1.Waste hierarchy (adapted from the European Commission 2016)
The waste hierarchy is similar to the 3R waste management strategy; reduce,
reuse and recycle (Fletcher 2008). Two similar strategies that prevent waste
are design for recycling and design for disassembly. Both facilitate recycling
by, e.g. making the products easy to take apart or easier to recycle by
avoiding material blends (Fletcher 2008).
MECHANICAL RECYCLING 2.2.Wanassi, Azzouz and Hassen (2015) used the best quality of recycled cotton
and produced yarn of 100 % recycled fibre with rotor pinning and concluded
that the rotor speed influence both the strength, irregularity and hairiness of
the yarn. The authors used pre-consumer yarn waste that was mechanically
recycled back to fibre. However, they do not go into the recycling process or
what defines the recycled fibre as best quality.
In another study by Wanassi, Azzouz, & Hassen (2016), they investigate
how to use cotton waste for producing a new yarn. The waste was in the
form of cotton yarns. The study was divided into two parts. In the first part,
the yarns were shredded in a Shirley Analyzer machine that has a sawtooth
roller and then analysed to find the optimal settings to get the highest quality
of the fibres. The authors investigated how the length of the yarn and
number of times the waste passed through the shredder affected the quality
of the reclaimed fibre. The effect of the two different factors was analysed
by neps count, short fibre count, weight yield, mean length and upper
quartile length. Neps are usually described as small entanglements in cotton
due to ginning and carding, and there is a relationship between maturity
index and neppiness (Nationalencyklopedin 2018; Rikipedia 2018).
However, Wanassi, Azzouz, & Hassen (2016) broadened the definition of
neps. In their study, it meant the entanglements caused by the harsh
recycling process. They also noted that the neps count increased with
6
increasing mechanical action which in this case is the number of passing
through the shredder.
In the second part of the study by Wanassi, Azzouz, & Hassen (2016), they
made yarns from the best fibres from the first part. The fibres were mixed
with 50 % virgin cotton, rotor spun in Ne 10, 15 and 20 and compared to
yarns made from 100 % virgin cotton. The yarns spun from the reclaimed
fibres had similar properties to the yarn of virgin fibre, but the total cost of
the yarn was a third lower than the virgin yarn. The Shirley Analyzer is a
machine that provides lint, dust and trash content for cotton. It is used in
research, as shredder by Wanassi, Azzouz, & Hassen (2016) but also used to
simulate flax cottonization line (SDL Atlas 2018; Foulk, Akin & Dodd
2008). However, no more examples of it being used as a shredder were
found.
Merati & Okamura (2004) studied how to make medium count yarns from
reclaimed fibres with a modified version of friction spinning. The authors
made a two-component yarn with reclaimed fibres in the core and cotton in
the sheath and a three component yarn with a filament of polyester in its
core and reclaimed fibres in the middle layer and cotton in the sheath. The
reclaimed fibres was a mix of 67 % cotton, 27 % Rayon, 4 % polyester, and
2 % acrylic. Both yarn types had the appearance of cotton yarn. For
comparison yarn of 100 % cotton and 100 %, reclaimed fibres were also
spun. All yarns were spun in 30, 40, 50, 60 and 70 tex. Spinning a 30 tex
yarn from reclaimed fibres was very difficult due to the frequent yarn
breaks. The two-component yarn was easy to produce in 30 tex, but it was
weak. The three-component 30 tex yarn was stronger than the 100 % virgin
cotton yarn.
In the study in International Textile Center (1994), they investigate how
mechanical recycled cotton from denim scraps can be mixed with low-grade
Pima cotton and rotor spun. (Pima cotton is regarded to be high-quality
cotton). The reclaimed fibres had a length of 0.84 in (21.3 mm) on average.
Several attempts were made to process the reclaimed fibres, one with only
reclaimed fibre and blends with 10 %, 20 % and 30 % Pima cotton. Only the
blends with more than 20 % Pima were possible to draw, and those also
spun well. From the yarns, new denim was produced but also different
knitted fabric.
Jonsson and Vuorinen (2016) investigated in their bachelor thesis
mechanical recycling of textiles used in hospital, shirts and t-shirts, of a
blend of cotton and polyester. The reclaimed fibres had a mean fibre length
of 9.1 mm after shredding.
Aronsson (2017) wrote in her master thesis about mechanical recycling. The
study focus on post-consumer cotton waste and 4 samples were shredded; t-
7
shirts of single jersey and denim jeans, both with a high and low degree of
wear fractions. The aim of the research was to investigate if the degree of
wear affects the result of the shredding focusing on fibre length changes.
The fibre length drop during shredding was analysed by measuring the fibre
length before and after. The fibre length for the single jersey with a low
degree of wear was 10 mm and 12 mm for a high degree of wear. The denim
fabric had a fibre length of 13 mm for both high and low degree of wear.
Before shredding the material with a low degree of wear had significantly
longer fibres than the material with a high degree of wear. Interestingly after
shredding, the material with a high degree of wear had a lower fibre length
reduction compared to the material with a low degree of wear. Also, the
single jersey made from finer and ring-spun yarn had a higher fibre length
reduction. The denim fabric had coarser yarn and was rotor-spun. Aronsson
emphasizes the need for developing the shredding process further to
maintain the fibre length.
The reclaimed fibres from denim jeans that Aronsson (2017) produced were
also analysed in a bachelor thesis by Agetorp and Lorentzon (2017). In their
study, they investigated the degree of polymerization (DP) and the
spinnability of the reclaimed fibres. The DP was lower for a high degree of
wear than for the low degree of wear. The authors noted that both fractions
had a DP high enough to qualify for dissolving pulp to make viscose and
lyocell. The reclaimed fibres were also mixed with virgin cotton in blends of
50 % and 20 % of reclaimed fibres and ring spun. 50 % reclaimed fibres
were difficult to spin but with 20 % it was easy to spin, and the tensile
strength was comparable to 100 % virgin cotton yarn. However, the
reclaimed fibres with a low degree of wear gave a stronger yarn the more
worn fibres.
In Namugas’ (2017) master thesis she investigated how to lower the
interfibre friction for cotton, polyester and their 50/50 blend. She also
studied the effect that mixing fibres of cotton and polyester has on interfibre
friction. The tests were made of virgin fibres that were pretreated with either
of 4 conditioners in different concentrations; spin finish, glycerol, PEG 1000
and PEG 4000 were evaluated. Namuga referred to the friction lowering
conditioners as lubricants in her work. The concentrations that were tested
were from 0.2 w%-10 w%. The fibres were sprayed with conditioners in
aqueous solutions. After drying, the treated fibres were carded to webs that
were cut into samples of 250 mm x 100 mm and tested in the tensile tester in
a novel method for interfibre friction measurement on carded webs. The
webs were carded two times. The method for interfibre friction used the
settings from the standard for fabric grab ASTM D 5034, with specimen
gauge 75 mm, load cell 0.1 kN and speed 300 mm/min. Average value
calculated from the test of the 10 samples. The results from the test on
8
carded webs were analysed, and the best concentration for PEG 4000 and
the concentration of glycerol that had the friction closest to untreated was
selected. For PEG 4000, 0.29 w% for polyester and cotton and 0.5 w% for
the blend was selected. However, for polyester, the lowest point was 0.71 w
% PEG 4000, but then the carded web could not be drawn into a sliver, and
therefore a lower concentration was selected for yarn spinning. Glycerol
was used in the concentrations of 1 w% for all fibres. Fibres of treated with
the selected concentrations were used in attempts to spin yarn from. It was
only possible to spin yarn from the treated polyester and the polycotton
treated with glycerol. The main findings in the thesis were those
conditioners in concentrations over 1.43 % lead to bad carding,
concentrations between 0.29-1 w% give good carding, but the cotton fibres
could not be spun into a yarn. She suggested that the amount that would be
suitable would be between 0.1-1 % depending on the material. She also
concluded that PEG 4000 is the treatment of tested conditioners that had the
best effect on both polyester and cotton.
CHEMICAL RECYCLING 2.3.It is possible to chemically recycled textile fibres of cellulose regenerated
fibres such as viscose, lyocell and modal (Östlund et al. 2015). A drawback
of the lyocell process is that it is more energy consuming than growing
cotton (Östlund et al. 2015).
In Agetorp & Lorentzon (2017) thesis as already mentioned, mechanical
recycled cotton fibre has a high enough DP for making regenerated fibres.
In another thesis, Björkquist (2017) writes that cotton from polycotton
sheets had an intrinsic viscosity suitable for regenerated fibres. The
polyester was removed from the sheets by depolymerization by alkaline
hydrolysis. The cellulose in a polycotton fabric can be dissolved by using
n-methylmorpholine-N-Oxide, the solvent used in the lyocell process
(Leonas 2017; Björkquist 2017).
Chemical recycling of polyester means that the polymer depolymerised back
to its monomers, which could be repolymerise back to polyester. The benefit
of chemical recycling of polyester is that the quality is equal to virgin fibres.
The process is still expensive and needs further development for working on
a bigger scale (Gullingsrud 2017).
FROM FIBRE TO YARN 2.4.The normal steps for yarn making by rotor spinning for short staple fibres
are fibre opening, carding, drawing and spinning. The fibres are usually
9
transported and stored in bales, which are highly pressed. The first step in
fibre opening takes place in the blow room were the compressed fibres are
open to flocks. The second step in fibre opening is the carding and in the
opening roller in the rotor spinning machine (Klein 2016a). The carding is
an essential role in the yarn spinning cycle. The are several functions of the
carding process, to further open and blend, to untangle the fibres and
arrange the parallel to each other, removes impurities and to produce a web
of the fibres(Carissoni, Dotti, Fleiss, Petaccia, & Pieri, 2002). The drawing
process is where the web from carding, called a card sliver, is processed into
a drawing sliver. The drawing is made in the drawing frame, which has
different zones for the draft. The drawing is divided into pre-draft, could
also be called break draft, and the main draft. In the drawing frame, there is
a doubling step where several card or drawing slivers, usually 4 or 8, is
drawn to one sliver; this makes the sliver more even. (Carissoni et al. 2002;
Klein 2014a). A normal total draft is between 4 and 8. In the drawing the
fibres get parallelised. Often there are several drawings of the slivers in a
textile mill. The drawing process is important for the quality of the yarn; a
yarn could never be better than the drawing sliver (Klein 2014a). With
drawing the fibres get straighten out, in the carded webs there is folded
fibres present (Carissoni et al. 2002).
For ring spinning the steps are fibre opening, carding, drawing, roving, and
spinning. In the roving frame, the sliver is made into roving, and this is a
preparatory step for ring spinning. In the rowing frame there are three
stages, drawing, twisting and winding (Carissoni et al. 2002).
Carding is both a step in spinning but also the manufacturing process for
webs for nonwoven production
YARN SPINNING 2.4.1.
There are several ways to spin yarn. Yarns can be ring spun; rotor spun,
friction spun, wrap yarn spun or with air-jet spinning. Ring – spinning is
the oldest technique and the one that is most diversely and gives the highest
level of quality (Nptel 2013). Ring spun yarn is smoother and stronger than
rotor spun (Eberle 2002). In rotor spun yarn the fibres are not so oriented,
and fibres are wrapped around the yarn compared to ring spun yarn that is
smoother (Eberle 2002). The structure of the yarn is presented in Figure 2
where there is an example of a ring spun yarn, and a rotor spun yarn. The
main disadvantage of ring spinning is the process speed, up to 40 m/min
compared to rotor spinning that could produce yarn over 200 m/min (Nptel
2013). For rotor spinning, fibre length is not as influential for the spinning
process and yarn quality as it is for ring spinning. With rotor spinning it is
possible to produce yarn from waste or recycled fibres of cotton (Klein
2014b). The twist in a yarn depends on for what use the yarn is produced.
Knitting yarn has lower twist than yarns for weaving, and weft yarns have
10
lower twist than warp yarn. The twist is an important factor for yarn
characterises as strength, density, elongation, hairiness and production.
(Furter & Meier 2009).
.
Figure 2. a) Ring spun yarn (2 ply cotton) b) Rotor spun yarn (1ply cotton)
ROTOR SPINNING 2.4.1.1.
Rotor spinning is a type of open-end spinning (Nptel 2013). For rotor
spinning, a roving is not needed and thus removing a step; it also has the
benefit of being up to six times faster than ring spinning. In Figure 3, a
schematic figure of how a rotor spinning machine works. The sliver is feed
into the machine, the feed roller transport the material to the opening roller
which opens it into single fibres again and cleans the material. The open
fibres are transported in a channel into the spinning rotor (Nptel 2013). The
rotor rapidly spinning gives the yarn its twist (Elhawary 2014). The fibres
that are fed into the rotor are incorporated into the open-end of the rotating
yarn that just been formed, hence the name open-end spinning. The delivery
rollers transport the formed yarn form the rotor through the navel (Elhawary
2014; Nptel 2013).
11
Figure 3. Schematic figure of the rotor spinning machine.
FIBRE LENGTH MEASUREMENT 2.5.The method used in this thesis is a novel method with image analysis. Fibre
length can be measured by different methods, both by hand, in different
machines and by image analysis. This overhaul is to give an understanding
of the most used method and another method that used image analysis.
Fibre length measurements often include different parameters that give an
overall picture of the quality of the fibres; Mean fibre length, variance,
standard deviation and coefficient of variance are the standard statistical
parameters. Other important is the short fibre content (SFC) which is the
fibres shorter than a specified length, for cotton, it is ½ inch (12.7 mm)
(Hearle & Morton 2008).
According to Hearle & Morton (2008), the obvious method for measuring
fibre length is by hand, one by one, with a ruler. They claim that is the most
reliable method but tedious. One way to measure by hand is to use the
standard SS-ISO 6889:2004 Determination of length and length distribution
of staple fibres. In the standard, there are three methods for measuring the
length and different methods for expressing the distribution. The standard is
for all staple fibres except bast fibres and fibres with a strong natural crimp
that makes it impossible to use the method. The prescribed number of fibres
measured is 500. Method A measures the fibres by hand on a graduated
glass plate with oil on it and a light tension with two forceps (SIS 2010a). In
method B the fibre length is measured with an opisometer is used on an
image of the fibre projected on a screen (SIS 2010a). An opisometer is a
tool for measuring the length of curved lines of, e.g. maps (Wikipedia
12
2018). Method C uses a semi-automatic device, WIRA Fibre Length
Machine, for measuring the fibre length under controlled tension (SIS
2010a).
Another method for fibre length measurement is by using a fibre array made
by a comb-sorter apparatus. The methods give accurate results but are too
expensive and time consuming for routine testing in the industry (Gordon
2006). An instrument that uses photoelectric sensors was first developed in
1940, Hertel invented the Fibrograph for cotton lint testing. The Fibrograph
is much faster than the array methods (Hearle & Morton 2008). The
principle of the Fibrograph is still the main method for measuring cotton
length, a fibre beard is held in a comb which is inserted into the machine
which measures the length by a photoelectric sensor (Hearle & Morton
2008: Gordon 2006). An instrument that uses that principle of measuring
length is the High Volume Instrument (HVI) (Hearle & Morton 2008).
Besides length the HVI measure strength, elongation and micronaire in
cotton (Gordon 2006). Another common instrument for measuring fibre
length is the Uster Advanced Fiber Information System (AFIS) that also
measures the fineness, measure maturity (of cotton), neps, trash and dust in
a sample (Hearle & Morton 2008; Gordon 2006). A sample of 0.5 g is
typically used, the instrument opens the samples and transfers them to an
air-stream, and each fibre then passes a photoelectric sensor that records the
length (Hearle & Morton 2008). A comparison between the HVI, AFIS and
a fibre array method showed that the result for SFC had a significant
difference and high variations (Cui, Calamari, Robert, Price, & Watson
2003). According to the authors, a major factor for this is the length
calibrations of the instruments.
In the study by Ikiz, Rust, Jasper and Trussel (2001), they developed a
method for fibre length measurement by image processing. The method
measured single fibres, and the accuracy was comparable to manual
measuring by hand, HVI and AFIS. The authors conclude that their method
could be used for calibrating existing instrument instead of measuring by
hand for calibration. Hearle and Morton mention another image processing
method, the instrument OFDA 4000 that is suitable for wool, animal and
most synthetic fibres. A computer analyses the image and the fibres
measured is typically 4000.
FRICTION IN TEXTILES 2.6.Friction plays a huge role in textiles; the friction is what holds fibres
together in the yarn, and yarns in the fabric. The ability to card fibres into a
web and the spinnability depend on the fibres’ frictional properties (Nair,
Patwardhan, & Nachane 2013; Robins, Rennell & Arnell 1988). The surface
properties of a fibre define it frictional behaviour and could be altered by
13
different lubricant agents (Kothari & Das 2008). For polyester fibres, spin
finish is added to lower friction and reduce static charges during processing.
The spin finish has more effect on fibres friction against metal than the fibre
against fibre friction (Robins, Rennell & Arnell 1988). Natural fibres
usually contain compounds that assist the spinning, e.g. wax or grease
(Kothari & Das 2008).
The basic law of friction is that the friction force, F, is proportional to the
normal force, N. The frictional force is not depending on the contact area.
The force that is needed to initiate sliding, the static friction force, is greater
than the force for maintaining the movement, the dynamic friction force
(Gupta 2008).
INTERFIBRE FRICTION 2.6.1.
The novel method for the interfibre friction of carded webs used by Namuga
(2017), described in detail in 2.2.
Another method for measuring the interfibre friction is the method
developed by Sinoimeri (2009) the interfibre friction is tested on an ordinary
sliver. The aim of the study was to find a method that suits short fibres. Two
carts with the sliver clamped are drawn apart, and the displacement and
force are recorded.
YARN PULL-OUT TEST 2.6.2.
Bilisik (2011) tested pull-out properties of polyester by pulling out single or
multiple threads. The fabric samples were fastened at the sides in a frame
with adjustable width, leaving the upper and lower edge free. From the
upper side of the sample, threads were pulled. The pull-out force depends on
the number of pulled threads and the fabric density, fabric structure and
treatment. The structures investigated were plain, ribs and satin woven
fabrics. Also, the effect of a softening agent was studied. The force needed
to pull-out single and multiple threads from plain weave was higher than for
ribs and satin fabrics. More force was needed to pull-put multiple threads
compared with single threads. In general, the force for untreated fabrics was
higher than for the untreated ones.
In a report for the Federal Aviation Administration, Shockey, Erlich &
Simons (2001) developed an experimental setup for the pull-out test with a
holder that grips the vertical edges of the sample. Thus the threads are
tensionless, and by moving the frame, several threads could be pulled from
the same sample. This, of course, requires that the distance is big enough not
to interfere with the results. One of the grips is fixed, and the other can be
adjusted to the width of the fabric. Their holder design is used in other
research, for example, Kirkwood et al. (2004).
14
Zhou, Chen, & Wells (2014) studied ballistic performance by doing pull-out
test from the fabric of ultra-high molecular weight polyethylene fibre
without clamping the fabric at its vertical edges. In their pull-out test, the
corners of the fabric were fastened in the lower clamp, leaving the frayed
threads in the middle free. The upper edge of the sample was frayed, and a
single yarn was fastened in the upper clamp.
MATERIALS 2.7.In this part the two textile materials and the two conditioners that are used
described.
COTTON 2.7.1.
Cotton is the world's most used natural fibre and second most used fibre
overall (Gullingsrud 2017; Textile Exchange 2017). The cotton
consumption 2018/2019 is expected to be 26.5 million tonnes (ICAC 2018).
Cotton fibre is a seed fibre, and it is almost pure cellulose. Cotton is soft and
has high absorbency and is therefore considered a comfortable material in,
e.g. apparel applications (Gullingsrud 2017). According to Gullingsrud
(2017), post-industrial waste could be made into new yarn, but due to short
fibre length it is often mixed with new fibres, and post-consumer waste is
mostly used for, e.g. nonwoven or insolation. Cotton can be both
mechanically and chemically recycled.
POLYESTER (PET) 2.7.2.
In this thesis, polyester is identified as the fibre made of Polyethylene
terephthalate (PET), which also is the most common polyester used in
textiles. Polyester is the most common fibre in the world. Polyester is a
synthetic fibre made from petroleum raw material (Gullingsrud 2017).
Polyester can be both mechanically and chemically recycled, and 7% of the
polyester is recycled (Textile Exchange 2017). The two major products of
Polyethylene terephthalate resin are synthetic fibre (up to 60%) and plastic
bottles (30%) (Plastic Insight 2017).
POLYETHYLENE GLYCOL (PEG) 2.7.3.
Polyethylene glycols are commonly used chemicals for various applications.
Polyethylene glycols is an approved additive as glazing agent for
supplements by the Swedish national food agency (Livsmedelsverket
2018a). Polyethylene glycol is water–soluble and used in various cosmetic
and pharmaceutical products (Britannica Academic 2018b). Polyethylene
glycol is an eco-friendly, inexpensive and recyclable chemical (Nagarapu,
Mallepalli, Yeramanchi, & Bantu 2011). Polyethylene glycol with different
molar mass is used for different applications
15
There are various uses for polyethylene glycols in the textile industry. They
are used as lubricants, softeners, conditioning agents and antistatic agents.
Polyethylene glycols can be used as lubricants for carding and spinning ,
weaving and knitting (Dow 2018).
GLYCEROL 2.7.4.
Glycerol is an approved by the Swedish national food agency as a food
additive when used as stabilisers, emulsifiers, thickeners and gelling agents
(Livsmedelsverket 2018b). It is used in cosmetics and pharmaceutical
products (Britannica Academic 2018a). Glycerol is safe for the
environment, biodegradable and nontoxic for humans (SDA 1990).
There are several applications for glycerol in textile processing; dyeing,
printing, as lubricants, sizing, softening and finishing (Leffingwell 1944;
SDA 1990).
16
MATERIALS 3.The conditioner used both for tests on fibres in the pre-study and on fabrics
in the main study were Polyethylene glycol 4000 (PEG 4000) from Merck
KGaA with CAS-no: 25322-68-3.
For the pre-study, the fibres that were used are in Table 1. Unfortunately,
the fibres that were presented as polyethylene terephthalate were later found
out to be a bicomponent polyester. With Raman spectroscopy, it was
confirmed that bicomponent polyester was not a pure polyester of
polyethylene terephthalate. The polyester Trevira 290, produced for a
nonwoven production was later confirmed by the manufacturer to contained
spin finish. The cotton fibres in Table 1 were used in both the pre-study, for
blending with the reclaimed fibre from the shredded material, and for
internal control of fibre length measurement by image analysis. For the
fibres the abbreviation that will be used is CO for cotton, BCPES for
bicomponent polyester and PET T290 for the polyester Trevira 290
Table 1. Virgin fibres used in pre-study. The cotton fibres are also used for blending and
fibre length measurement.
Fibre Length
[mm]
Titer
Cotton (CO) Ca 26
Bicomponent polyester (BCPES) staple fibre
with low Tm sheath and conventional PET core
52 4 denier
Polyester Trevira 290 for nonwoven 38 1.7 dtex
The fabrics used in the main study had similar specifications. All the fabrics
were plain weave, with a weight per meter square (GMS) of 145 g/m2. All
fabrics were ordered with the request to be made of ring spun, staple fibre
yarn. All fabrics are in Table 2. For the fabrics the abbreviation that will be
used is CO for cotton, PET for polyester and CO/PET for the polycotton.
Table 2. Fabrics used for main-study
Material Construction GSM weight
from supplier
Cotton (CO)
Ringspun
Woven, plain weave 145g
Polyester (PET) Dorado White.
Staple fibre weft, ringspun.
Multifilament warp*
Woven, plain weave 145 g
Polycotton
50 % CO/50 % PET (CO/PET) Ringspun
Woven, plain weave 145 g
* Result of fabric analyses
17
Fabrics treated by Catherine Namuga that were tested in the thesis are listed
in Table 3. The conditioners were applied by spraying with a hand-held
pressure sprayer. The concentrations are in weight percent (w%). Three of
the fabric samples were treated with different concentrations of
polyethylene glycol 4000, see Table 3. The rest were treated with 1 w%
glycerol for all fabrics. For conditioner selections see Namuga1 (2017). The
fabrics that Namuga treated were from the same roll as the fabric used in
this thesis.
Table 3.Fabric treated by Catherine Namuga
Cotton Polyester Polycotton
0.29 w% PEG 4000 0.71 w% PEG 4000 0.5 w% PEG 4000
1 w% Glycerol 1 w% Glycerol 1 w% Glycerol
1 The concentrations for the treated fabrics were from e-mail conversation with Catherine
Namuga 2018-04-24
18
METHODS 4.A pre-study was carried out on fibres in order to decide the concentration of
conditioners for the fabric that was to be shredded. Figure 4 illustrates a
schematic overview of the thesis. The first part describes the methods for
the pre-study. The main study focuses on the methods for treatment and
shredding of the fabrics and the analyses and test of the shredded material.
The methods were chosen from the literature study. A limitation was the test
equipment available. The fabrics after shredding will be denoted as the
shredded material, and the fibres from the shredded material will be referred
to as reclaimed fibres to separate them from the virgin fibres.
Figure 4. Schematic overview of the pre-study and main study
PRE-STUDY 4.1.In the pre-study fibres were treated and carded into webs for testing the
interfibre friction and select the concentration for the fabrics in the main
study. The fibres and conditioners tested are listed in section 3. The test
method for identifying fibres, Raman spectroscopy, is briefly described in
this part. Figure 5 shows the steps in the pre-study.
Figure 5. Steps in pre-study
19
FIBRE OPENING 4.1.1.
The fibres for treatment with conditioner were opened in the fibre opener, a
small La Roche edge shredder that here served as a lab scale fibre opener
connected to a domestic central vacuum cleaning unit that collects the
opened fibres. After treatment and before carding the fibres were opened a
second time.
FIBRE TREATMENT 4.1.2.
The conditioner, PEG 4000 was sprayed on to the fibres with a hand-held
pressure sprayer. To prepare the conditioning solution, the dry weight of
PEG 4000 was measured using a 5-digit scale and mixing with deionized
water at room temperature. The amounts of conditioner were calculated
from the weight of the samples and are listed in Table 4 in weight percent
(w%).
Table 4. Concentrations of PEG 4000 for fibres in weight percent
Fibres PEG 4000
CO 0.1 w % 0.2 w% 0.3 w%
BCPES 0.1 w% 0.2 w% 0.3 w%
CO 50 %
/BCPES 50
%
0.1 w % 0.15 w% 0.2 w% 0.3 w%
CO 50 %
/BCPES 50
%
0.1 w % 0.15 w% 0.2 w%
PET T290 0.1 w% 0.2 w% 0.3 w%
Before spraying with conditioner, a test with only water was performed to
check how well the liquid wet the fibre. A test batch of 70 g of cotton and
70 g polyester was prepared. The cotton fibres were sprayed with 200 g of
water and the polyester with 100 g of water, but there were still dry fibres.
The amount of water was increased to 300 g of water to get sufficient
wetting of the fibres. All fibres were treated with the same amount of liquid,
with different concentrations of PEG 4000 or water only.
CARDING 4.1.3.
Carding was done in a Mesdan Lab 337A Laboratory carding machine. Each
web for testing had a batch size of 70 g opened fibres before carding. After
the first and second carding, the web was folded into three layers and rotated
90° before being fed into the machine again. After the third carding, the web
was cut from the collection drum and placed on a paper that was folded
around the webs to protect them until testing.
20
NOVEL METHOD FOR TENSILE TESTING OF CARDED 4.1.4.
WEBS
The carded webs were tested with the method described by Namuga (2017)
to obtain maximum force. The maximum force here is the force for static
friction, and it is the force required for the fibres to start sliding against each
other. Figure 6A shows the sample setup. The samples were tested in a
Mesdan electromechanical tensile tester with the pneumatic grips. The
setting for fabric grab ASTM D 5034 test was used, where the gauge length
was 75 mm, the load cell 0.1 kN and the speed 300 mm/min. The samples
size was 25 cm x 10 cm and were cut in the length direction of the web, as
shown in Figure 6B. From each web, 10 samples were cut. Figure 6C is an
example of how 10 samples were cut from a web. The side of the carded
webs was uneven, and the top and nether edge cut and was therefore
discarded, marked with a dashed line in Figure 6C. The samples were
weighted on a 2-digit scale. The fibre samples were conditioned for testing
in a standard atmosphere of 65 % humidity and 20° C.
Figure 6. A) Sample of the carded web in the tensile tester. B) Dimensions of sample C)
10 samples from a carded web
RAMAN SPECTROSCOPY 4.1.5.
Raman spectroscopy was used to identify the material. Every molecule has
its own unique curve, and it could be used to identify material by Raman or
similar techniques. The equipment was a Modular Raman Spectroscopy
system with parts from Ocean Optics; QE Pro High-Performance
Spectrometer, a Turnkey Raman Laser and from Inphotonics Laboratory
probe and Sample Holder. The data from the spectrometer were collected by
the software Oceanview 1.6.7 and the graph produced in Excel. The Raman
A B C
21
curve for the bicomponent polyester was compared with the polyester fabric
and with PET curves in literature, see PET curve on page 59 in the article by
Cho (2007).
MAIN STUDY 4.2.The main study is divided into two parts. First, methods for fabric treatment,
analyses and shredding. In the second part, the methods for the shredded
material.
FABRIC TREATMENT, ANALYSES AND SHREDDING 4.2.1.
In Figure 7 is an overview of the methods used for the fabrics. In the figure,
there are two sources of material, the fabric for treatment in this study and
the fabric already treated by Namuga, described in section 3, page 18.
Figure 7. Methods used for fabrics. The material treated by Namuga are described in
section 3. Materials on page 18. The different test methods for the fabrics are described
in section 4.2.1.2 and pictured in Figure 8.
TREATMENT OF FABRICS 4.2.1.1.
First, all fabrics were washed with household detergent for white fabrics in
WASCOTOR FOM 71 MP which have the programs from standard SS-EN
ISO 6330:2012 Textiles - Domestic washing and drying procedures for
textile testing (SIS 2012b). Polyester and polycotton have been washed at 60
degrees in the program 2a from SS-EN ISO 6330:2012. The cotton fabric
was first washed at 60 degrees at program 2a. After the cotton fabric was
washed the first time, it was controlled and found that the seizing from
weaving was still on the fabric. The fabric was then washed twice at 90
degrees in program 1a from SS-EN ISO 6330:2012 to remove the sizing.
22
The sizing was detected, and its removal was monitored by calcium iodine
staining.
The fabrics were prepared using a Mathis HVF lab scale foulard to achieve
an even distribution of the conditioner. Tests were done prior to the foulard
process to found out which pressure should be used and to calculate the
liquid uptake. The uptake was measured by testing one piece of each fabric
at different pressure with water as bath liquid in the foulard and weighing
the fabric before and after to be able to calculate the liquid needed. The
pressure was increased to lower the uptake to ensure that the excess liquid
was pressed out and did not drip from the wet fabric. The measured liquid
uptake of the fabrics was used to calculate the water amount in the aqueous
solutions of the conditioners, in Appendix VI, Table 22, is calculations for
concentration for treating the fabrics. To confirm that the actual uptake was
as calculated two samples of each fabric type were weighed during the
process to be able to confirm the uptake. Since the foulard press out excess
liquid, the bath volume had to be larger than the calculated uptake; the bath
volume was increased by 10 % see equation 1 for bath volume 1. The bath
liquid was mixed for the whole fabric sample, and the container for the bath
in the foulard was refilled during the process. After the process, excess
liquid after the process was collected from the bath container and weighed.
The fabrics were flat dried. In Table 5 are all prepared fabrics both for
shredding and testing.
𝑓𝑎𝑏𝑟𝑖𝑐 𝑤𝑒𝑖𝑔ℎ𝑡 ∗ 𝑤𝑎𝑡𝑒𝑟 𝑢𝑝𝑡𝑎𝑘𝑒 + 10 % = 𝐵𝑎𝑡ℎ 𝑣𝑜𝑙𝑢𝑚𝑒 1 (1)
Fabric samples with different concentrations of the conditioners were also
prepared, to compare to the result from carded webs. In Table 5 are all
fabrics prepared for shredding and testing. The same settings for the foulard
were used, but the bath liquid was increased by 20 % since only one piece of
approximately 100cm x 75 cm was processed, and the bath had to wet the
piece fully. See equation 2 for bath volume 2. The fabrics were flat dried.
𝑓𝑎𝑏𝑟𝑖𝑐 𝑤𝑒𝑖𝑔𝑡ℎ ∗ 𝑤𝑎𝑡𝑒𝑟 𝑢𝑝𝑡𝑎𝑘𝑒 + 20 % = 𝐵𝑎𝑡ℎ 𝑣𝑜𝑙𝑢𝑚𝑒 2 (2)
Table 5. Fabric samples for shredding and different test
For shredding and fabric analysis For fabric analysis
Cotton Polyester Polycotton Cotton Polyester Polycotton
Untreated Untreated Untreated 0.2 w%
PEG 4000
0.1 w%
PEG 4000
0.2 w%
PEG 4000
0.1 w%
PEG 4000
0.2 w%
PEG 4000
0.1 w%
PEG 4000
0.15 w%
PEG 4000
0.15 w%
PEG 4000
0.15 w%
PEG 4000
23
ANALYSES OF THE FABRICS 4.2.1.2.
One piece from each sample in Table 3 (page 18) and Table 5 of
approximately 100 cm x 75 cm was conditioned for testing in a standard
atmosphere of 65 % humidity and 20° C. For the untreated fabric two extra
pieces of each type were also prepared for further testing. An overview of
the methods for analyses of the fabrics is found in Figure 8. For all untreated
samples and all treated polyester samples, the tensile strength of the yarn
was tested. The pull-out test was done for all samples. For the untreated
samples the properties of the fabric were analysed; the GSM weight, the
number of threads in warp and weft, linear density and yarn type. The fibre
lengths of the yarns in the fabric were measured by image analysing.
Figure 8. Analyses on fabric
LINEAR DENSITY FOR YARNS FROM FABRICS
To calculate the linear density of eh yarn removed from fabric a modified
version of SS-ISO 7211-5 Determination of linear density of yarn removed
from fabric - method A (SIS 2012a) were used. Two pieces of fabric,
measuring 50 cm x 6 cm were cut in both warp and weft directions. Due to
no apparatus was available for determinate the crimp, the measuring was
done by hand with a ruler and a small tension for straightening out the
crimp. The length was measured for the first 10 threads, and a total of 50
threads were taken from each piece. The weight of 100 threads was
measured on a 5-digit scale, and from the length and weight, the linear
density in tex (g/1000 m) was calculated according to equation 3.
𝑀𝑎𝑠𝑠 𝑜𝑓 𝑡ℎ𝑟𝑒𝑎𝑑𝑠 𝑡𝑎𝑘𝑒𝑛 𝑓𝑟𝑜𝑚 𝑓𝑎𝑏𝑟𝑖𝑐 (𝑔)∗1000
𝑀𝑒𝑎𝑛 𝑙𝑒𝑛𝑔𝑡ℎ 𝑓𝑜𝑟 𝑜𝑛𝑒 𝑡ℎ𝑟𝑒𝑎𝑑∗𝑛𝑢𝑚𝑏𝑒𝑟 𝑜𝑓 𝑡ℎ𝑟𝑒𝑎𝑑𝑠 = 𝑡𝑒𝑥 (3)
TENSILE TESTING OF YARNS FROM TREATED FABRICS
The tensile strength of the yarns was tested according to standard SS-ISO
2062 Yarns from packages - Determination of single-end breaking force and
elongation at break using a constant rate of extension (CRE) tester (SIS
2010b). Due to the limited amount of fabric set aside for testing, the
sampling procedure was modified. A square of 40 cm x 40 cm was cut from
the conditioned samples. 20 threads were tested from warp and weft, 10
24
threads from each side of the square. The yarns from the fabric were tested
in a Mestan tensile tester with pneumatic grips and 0.1 kN. The gauge
length was 250 mm, and the speed was 250 mm/min. The preload was
according to standard, 0.5 cN/tex ± 0.1 cN/tex for conditioned samples
using the linear density in tex calculated for the yarns from the fabric.
WEIGHT MEASUREMENT
The GSM weight was measured according to SS-ISO 6348 Textiles -
Determination of mass - Vocabulary (SIS 1990). Five samples were cut by a
GSM-cutter from conditioned fabric and weighed on a 5-digit scale, and the
weight of a square meter was calculated.
FIBRE LENGTH MEASUREMENT
The fibre length was measured with a novel method that is non validated.
The length of the fibres in the fabrics was analysed with the same method
developed for the reclaimed fibres from the shredded material. The method
uses image analysis to calculate the fibre length from a picture. The image is
converted from colour to black and white. The image is cut into small strips,
a single fibre is identified, and its length was measured in pixels. It was
compared with the number of pixels of the known width of the sample. The
resolution was 1200 pixels per inch (24.5 mm). Samples were prepared by
taking two threads of 50 cm from warp and weft of each fabric, except the
multifilament warp for the polyester. The threads were disintegrated
carefully. The yarns were untwisted by hand, and the fibres next to the ends
of the yarn were discarded due to cut fibres. The fibres were placed on the
adhesive side of the transparent tape with the assistance of forceps. The size
of the tape was 20 cm x 5 cm. The tape was placed on a printed green paper
as shown in Figure 9, pictures of all samples are in Appendix VIII, Figure
29 and 30. Further, the virgin cotton fibres used for pre-study and blending
with reclaimed fibres for yarn production were analysed in the same way for
internal control of the method.
Figure 9. Sample for fibre length measurement, fibres from the cotton weft
YARN PULL-OUT TEST
The interfibre friction was tested both on carded webs as described in 4.1.4
but the friction was also tested in a pull-out test on the fabrics. The samples
were cut in the form presented in Figure 10. As the test equipment use in
25
Shockey, Erlich & Simons (2001) was not available, a modified version of
the test in an article by Zhou, Chen, & Wells (2014), testing samples
without special equipment was used. For the pull-out test, the lower part of
the sample was fastened in the nether grip, used for tensile testing for e.g.
fabric strips. The single thread in the upper part of the sample was fastened
in the pneumatic grip that was also used for the carded sample. See Figure
10b for the test set up. The load cell used was 0.1 kN, and the speed 100
mm/min and the gauge length was 60 mm. A test was successful if the yarn
was pulled out completely without breaking. The samples were prepared by
removing the threads perpendicular to the test direction so that one thread
could be pulled out from the sample, see Figure 10a, b and c. A 10 mm cut
with a scalpel was made perpendicular to the test direction and thus making
it possible to pull out a thread from the sample. In Figure 10 a and c, the cut
is 0.5 cm over the lower point where the sample is fastened in the machine.
The measurement of a sample is shown in Figure 10c. All samples were
labelled and marked where to be cut and fastened in the lower grip. 10
samples were made from each fabric in the weft direction.
Figure 10. a) sample for pull out test, the cut is marked. b) set up in the tensile tester, the
upper grip pulls one thread from the sample. c) Schematic figure of a sample with the
measurements
SHREDDING AND CUTTING 4.2.1.3.
The fabrics that were shredded are listed in Table 6. Prior to shredding the
fabrics had to be cut into smaller pieces before being processed in the
shredder. As the cutter only could process pieces less than 1 m2, all fabrics
were cut accordingly. The cutter was an NSX-QD350 from Qing Dao New
a b c
26
Shunxing Environmental Protection and Technology Co with rotation
knives. The fabric had to pass through it 3-4 times to be cut in small enough
pieces for the shredder.
The fabric was shredded in NSX-FS1040, with one drum with 8 mm long
saw teeth, that were connected with NSX- QT310 which had smaller drums
with 4 mm long saw teeth. Both machines were from Qing Dao New
Shunxing Environmental Protection and Technology Co and were slightly
modified by Swerea for safety reasons. In Figure 11, a schematic figure of
the machine is presented, A is the drum NSX-FS1040 and b, c and d are the
drums in NSX- QT310. The top of the machine was not fully covered to be
able to control the process more. The fabric pieces were fed evenly into the
machine, and an even flow of material was sustained in the machine. The
material was run through the machine twice. Specifications for the cutter
and both machines in the shredder are in Appendix XI.
Figure 11. Schematic figure of the shredding machine (Jonsson & Vuorinen 2016)
2
Table 6. Fabrics that were shredded
Cotton Polyester Polycotton
Untreated Untreated Untreated
0.1 w% PEG 4000 0.2 w% PEG 4000 0.1 w% PEG 4000
0.29 w% PEG 4000 0.71 w% PEG 4000
0.5 w% PEG 4000
1 w% glycerol
1 w% glycerol
1 w% glycerol
SHREDDED MATERIALS 4.2.2.
The shredded material was analysed, both the length of the fibres and visual
analysis of neps and unopened threads. For the fibre length measurement
and visual analysis, a random sample was taken from the reclaimed fibres,
ten tufts with a total weight of 2.5 g. The shredded material was tested in
each step, from carding and drawing to spinning of yarn. The properties of
2 Reprinted with permission from the authors.
27
the produced yarns were analysed; the linear density calculated and analysed
visually. The tenacity of the yarns tenacity was tested in the tensile tester. In
Figure 12 are the methods or the shredded material.
Figure 12. Methods used for shredded material.
FIBRE LENGTH MEASUREMENT 4.2.2.1.
Fibre length measurement for the reclaimed fibres was done with a novel
method that is non-validated, same as described in 4.2.1.1. The method uses
image analysis to calculate the fibre length from a picture. The fibres from
the random samples were carded by hand with carders and from the carded
fibres a small sample of 0.02 g was taken and carefully aligning by hand and
placed with the aid of forceps on the adhesive side of a transparent tape of
20 cm x 5 cm and placed on printed green paper, as shown in Figure 13. The
sample was scanned in high resolution and then analysed by the software. In
Figure 13, an example of a sample is shown, and in Appendix VIII, Figure
31-33 are pictures of all samples analysed with the fibre length
measurement.
Figure 13. Picture of a sample, Polyester 0.2 w% PEG 4000 for fibre length
measurement.
28
VISUAL ANALYSIS OF SHREDDED MATERIAL 4.2.2.2.
From the random sample prepared from the shredded material, a small
sample was carded from each material. Of the carded fibres from the
random sample in 4.2.2.1, a small amount of 0.25 g was analysed, and the
neps and unopened threads were counted. The neps and unopened threads
were then placed on the adhesive side of a transparent tape 5 cm x 20 cm
and placed on black paper and analysed visually. Figure 14 shows an
example of one sample. All samples are found in Appendix IX, Figure 34-
36. The samples on paper were then scanned, and pictures of neps,
unopened threads and of melted fibres in the material were taken with
Plexgear USB-microscope.
Figure 14. Neps and threads from polyester treated with glycerol.
CARDING 4.2.2.3.
Carding was made in a Mesdan 337A Laboratory carding machine, same as
described in 4.1.3. To investigate if the shredded material could form a web
a random sample of 30 g of each shredded material was tested. For sliver
production, the shredded material was carded 2 times in batches of 20 g or
25 g to achieve different thicknesses of the slivers. The reclaimed fibres
were also blended with 50% virgin cotton fibres and carded in batches with
9 g of each. Also, test batches of 8 g and 10 g were made to obtain a suitable
tex count for the sliver. The fibres were open by hand and blended in the
carding machine In order to make a reference yarn sample, carded webs of
virgin cotton were also made. The carded web was collected from the drum
and folded into a thick card sliver that was processed in the drawing frame.
SLIVER 4.2.2.4.
The slivers were made in a Mesdan 3371 Stiro-roving lab machine, drawing
frame for making sliver and rowing. The slivers were passed through four
sets of rollers in the drawing frame. In Figure 15 the different zones are
labelled. The draft is divided into the pre-draft and main draft. The shaping
of the silver is in the last zone. The slivers pass through a slot and a pair of
rollers that further shape it. In the Stiro-roving machine, the drawing is
altered by changing the sprockets, see Figure 16. The size of the sprockets
determines the speed of the rollers in the drawing frame. The machine has
four sprockets that could be changed labelled A, B, C and D in Figure 16.
To be able to alter the drawing more in order to achieve a more gentle
drawing, larger new sprockets were made. New longer chains were made to
29
work with the larger sprockets. The sprockets made had 38, 42, 46 and 52
teeth. The sprockets available with the machine had with 20-34 teeth. The
finished slivers were weighed and the length measured to calculate an
approximate linear density in tex.
Figure 15. The function of the different zones in the drawing frame.
Figure 16. Sprockets that could be changed in the machine to alter the draft
ROTOR SPINNING 4.2.2.5.
The rotor spinning was done in an SDL Atlas Quickapin, a lab scale machine
with a fibre opener and one rotor spinning unit. The slivers were fed directly
into the machine and the opening roller removed short fibres, neps and
threads that were collected in a trash box under the machine. A 40 mm rotor
and OS21 opening roller were used. The settings that could be altered were
the total draft, rotor speed [rpm] and delivery [m/min]. The total draft was
calculated as in equation 4. For calculating the delivery as in equation 5, the
rotor speed and yarn alpha had to be decided. Rotor speed is the speed of the
rotor, and yarn alpha is a factor for the twist in the yarn. For reclaimed
fibres, which are short, a higher twist was chosen for the yarn. Notice that
30
since the fibres are short, the final twist is not necessarily as high as the
twist factor chosen.
𝑛𝑜𝑚𝑖𝑛𝑎𝑙 𝑡𝑜𝑡𝑎𝑙 𝑑𝑟𝑎𝑓𝑡 =𝑡𝑒𝑥 𝑜𝑓 𝑠𝑙𝑖𝑣𝑒𝑟
𝑒𝑥𝑝𝑒𝑐𝑡𝑒𝑑 𝑦𝑎𝑟𝑛 𝑡𝑒𝑥 (4)
𝑑𝑒𝑙𝑖𝑣𝑒𝑟𝑦 =𝑟𝑜𝑡𝑜𝑟 𝑠𝑝𝑒𝑒𝑑
(√𝑡𝑜𝑡𝑎𝑙 𝑑𝑟𝑎𝑓𝑡
𝑘𝑡𝑒𝑥 × 𝛼)
(5)
LINEAR DENSITY FOR ROTOR SPUN YARNS 4.2.2.6.
From each yarn, 10 m was reeled and made into a small skein that was
weighed, and the linear density in tex was calculated with equation 6. For
the yarn made of reclaimed fibres of polyester treated with 0.2 w% PEG
4000, that had problems during spinning, two skeins of 5 m was done
instead.
𝑔 / 𝑚 ∗ 1000 = 𝑡𝑒𝑥 (6)
WASHING OF ROTOR SPUN YARNS 4.2.2.7.
A sample of 10 m of each of the rotor spun yarns were washed, except the
yarn of PET 0.2 w% PEG 4000 since there was not enough yarn. The
washing was done to remove the treatment with PEG 4000, to test if the
remaining conditioner affects the tenacity of the yarns. The yarns were
reeled and made into a small skein to avoid the yarns getting tangled during
washing. The skeins were washed by hand in cold water with liquid
household detergent and rinsed 3 times in cold water. The yarns were drip
dried.
The washed yarn lengths were measured again since washing could alter the
length and then weighed. From the length and weight, the linear density was
calculated as in 4.2.2.6.
TENSILE STRENGTH OF YARNS FROM ROTOR SPINNING 4.2.2.8.
The tensile strength of the rotor spun yarns and washed yarns were tested
according to standard SS-ISO 2062 Yarns from packages - Determination of
single-end breaking force and elongation at break using a constant rate of
extension (CRE) tester (SIS 2010b). The sampling procedure was not
possible to follow due to very limited amounts of the rotor spun yarn. The
yarns from the linear density measurement were also used for the tensile
tester. For the washed yarns the 10 m prepared in 4.2.2.7 was used. The
gauge length was 250 mm, and the speed was 250 mm/min, and the preload
was according to standard 0.5 cN/tex ± 0.1 cN/tex for conditioned samples
and the linear density that been calculated for each yarn. The tensile strength
per tex, tenacity [cN/tex], was used to compare the yarns. The number of
samples tested was 20.
31
VISUAL ANALYSIS OF YARN 4.2.2.9.
The yarn was wrapped around black paper 6 cm x 10 cm to visually analyse
how even the yarn was and if there were neps present in the yarn. All yarns
of reclaimed fibres were compared with the rotor spun reference yarn of
virgin cotton. In Appendix X pictures of all yarn are presented in Table 25.
ANALYSIS OF DATA AND STATISTIC 4.3.The data were analysed in Excel for calculations and graphs, and the
statistics were analysed in Minitab 17, where ANOVA and Tukey Pairwise
Comparison and Tukey Simultaneous Test Differences of Means were
made. ANOVA is an analysis of variance between the mean of the samples.
The null hypothesis used was that all means are equal and the alternative
hypothesis is that at least one mean different. A significance level of 0.05
has been used. If the p-value is less than 0.05 the null hypothesis could be
discarded and at least one mean different. A Tukey pairwise comparison test
was used to find which means that are significantly different and Tukey
Simultaneous Test Differences of Means for adjusted p-values of the means
that are significantly different.
32
RESULTS 5.The result is divided into two parts. First, are the results of the pre-study
done on fibres. Secondly, is the main study with the results from fabric
treatments, analyses, shredding and the shredded materials.
RESULTS FROM PRE-STUDY 5.1.To continue on Namugas (2017) research, further studies on the
concentration of PEG 4000 were done. Namuga had chosen a concentration
of 0.29 w% of treatment both cotton and polyester. This concentration gave
lower interfibre friction and good carding. From the polyester it was
possible to ring spin a yarn, but not from the cotton. Therefore, it was
decided to investigate the concentrations around 0.29 w% in this study. The
results from the fibres with different concentration of PEG 4000 were used
for selecting the concentrations for the fabrics. In the test method for
interfibre friction, a carded web is tested in a tensile tester. The test of
interfibre friction shows the maximum force from the tensile test of the
carded webs. In Figure 17 are the results of the measurements of interfibre
friction for cotton, bicomponent polyester and a blend of cotton and
bicomponent polyester. For both cotton and bicomponent polyester, the
concentrations tested was 0.1, 0.2 and 0.3 w% PEG 4000. For cotton fibres,
the lowest friction force was when the concentration was 0.1 w% of PEG
4000 as seen in Figure 17. Bicomponent polyester had the lowest friction
force when the concentration of PEG 4000 was 0.2 w%. This is also
statistically confirmed with ANOVA as shown in Table 7 and with Tukey
pairwise comparison in Table 8. The full ANOVA and Tukey pairwise
comparison is in Appendix I. Since cotton, and bicomponent polyester had
different concentrations for their lowest friction force, a third concentration
between (0.15) them were also tested for the mixture of 50 % cotton and 50
% bicomponent polyester but not the concentration of 0.3 w% since it was
not deemed optimal for any of the webs. For the mixture, the results for the
friction force were lowest at 0.1 w% of PEG 4000 but were not confirmed in
ANOVA or in Tukey pairwise comparison. Also, an additional test on
carded webs was conducted with 75 % cotton and 25 % bicomponent
polyester with the same concentration as the other blend of cotton and
bicomponent polyester, no results were significant, see Table 7 and 8.
The concentrations for treating the fabrics in the main study were selected
from the results from the test of the carded webs in the pre-study, 0.1 w%
for cotton and polycotton and 0.2 w% for polyester.
33
Figure 17. Results from tensile testing of fibre webs treated with different concentration
of PEG 4000.
Table 7. P-values and F-values from ANOVA for tested samples of fibre webs.
CO PEG
4000
BCPES
PEG 4000
50 CO/50 BCPES
PEG 4000
75CO/25 BCPES
PEG 4000
P-value 0.006+
0.000+
0.091-
0.212-
F-value 4.82 127.06 2.33 1.58
Table 8. Adjusted p-values from Tukey Pairwise Comparisons between untreated and
treated with different concentration of PEG 4000.
w% PEG
4000
100 %
CO
100 %
BCPES
CO 50 %/
BCPES 50%
CO 75 %/ PET
25%
0.1 0.010+ 0.000
+ 0.498
- 0.943
-
0.15 - - 0.877- 0.522
-
0.2 0.083- 0.000
+ 0.690
- 0.759
-
0.3 0.904- 0.000
+ - -
The polyester Trevira 290 was also tested in following the concentrations of
PEG 4000; 0.1, 0.2 and 0.3 w% and treated with water only. The samples of
polyester Trevira 290 was accidentally tested on a larger gauge length of 87
mm due to a mechanical problem with the machine. The results are in
Figure 18.
34
Figure 18. Polyester Trevira 290 tested with different concentrations of PEG 4000.
RESULTS FROM THE MAIN STUDY 5.2.In the main study are the results from the fabrics and the results from the
material shredded from the fabrics presented.
FABRIC TREATMENT, ANALYSES AND SHREDDING 5.2.1.
In the first part are the results of the test for fabric preparation and the
analysis of the untreated fabric properties and the test results from the fabric
samples.
FABRIC PREPARATION 5.2.1.1.
The result of the test of the water uptake for the different fabrics is shown in
Table 9. The pressure was adjusted to lower the water uptake of the cotton
and polyester to around 80 %; as seen in Table 9. The uptake was measured
twice during the preparation to ensure that it was accurate.
Table 9. Settings used for foulard.
Fabric Pressure w% water uptake
Cotton 3.5 bar 82
Polyester 4 bar 82
Polycotton 2 bar 69
ANALYSIS OF FABRIC 5.2.1.2.
The analyses of the yarns from the fabric are presented in Table 10. All
yarns were ring spun of staple fibres except the warp of the polyester fabric,
35
which was a multifilament yarn. Before washing all fabrics had an
approximate weight of 145 grams per square meter, but after washing both
the cotton and polyester fabric have shrunk and thus the weight per square
meter increased.
Table 10. Analyses of fabrics.
Fabric Yarn type GMS after
washing
Threads/
cm
Tex
Cotton Warp and weft: ring spun
staple fibre
170 Warp: 26
Weft: 25.8
Warp: 28.5
Weft: 27.7
Polyester Warp: Multifilament
Weft: Ring spun staple fibre
152 Warp: 29.4
Weft: 22.2
Warp: 17.8
Weft: 38.9
Cotton/
Polyester
Warp and weft: ring spun
staple fibre
142 Warp: 30.7
Weft: 25.4
Warp: 23.2
Weft: 23.1
TENSILE STRENGTH OF YARNS FROM FABRICS 5.2.1.3.
The tensile strength of the yarns from the untreated fabrics and all treated
polyester fabric samples are presented in Table 11. An ANOVA with a
Tukey test of the result from the polyester only showed significant lower
strength for one of the treated samples, the one treated with glycerol,
compared to the untreated sample for weft yarn. For polyester warp yarn
there was no result that the treatments lower the strength. For the untreated
samples, the polyester and polycotton warps were significantly stronger than
their weft, but for the cotton yarns, there was no significant difference. Full
ANOVA and Tukey test for yarns from fabric are in Appendix II.
Table 11. Mean tensile strength and tenacity of yarns from fabrics.
Sample Weft
strength
[cN]
Weft
tenacity
[cN/tex]
Warp
Strength
[cN]
Warp
tenacity
[cN/tex]
PET untreated 688.15 17.65 596.7 33.5
PET 0.1 w% PEG
4000
670.6 17.25 617.95 34.7
PET 0.15 w%
PEG 4000
691.55 17.85 614.5 34.6
PET 0.2 w% PEG
4000
647.05 16.65 617.15 34.6
PET 0.71 w%
PEG 4000
697.1 17.95 614.5 34.6
PET glycerol 638.2 16.35 603 33.75
CO untreated 418.2 15.15 463 16.25
CO/PET
untreated
446.05 19.4 479.5 20.75
36
FIBRE LENGTH MEASUREMENT OF FIBRES FROM FABRICS 5.2.1.4.
The fibre length measurements of cotton fibres from the fabrics have an
average of 27.6 mm for weft and 20.6 mm for warp. For the polyester fabric,
the average length of weft yarn was 28 mm. The polyester yarn in the warp
was a multifilament yarn, and the fibre length for multifilament was not
measured since it is the length of the yarn. The average fibre length for the
polycotton fabric was 28.8 mm for weft and 25.4 mm for weft. All results
are in Table 12. Appendix VIII has pictures of all samples for fibre length
measurement.
Table 12. Fibre length measurement of fibres from fabrics.
Sample Mean length fibres [mm]
CO Weft 27.6
CO Warp 20.6
PET Weft 28
CO/PET Weft 28.8
CO/PET Warp 25.4
PULL-OUT TEST 5.2.1.5.
For the pull-out test for cotton and polycotton, there was a problem with
some of the samples where the yarn broke before being completely pulled
out. This means that the pull-out force was higher than the yarn strength.
However, this did not happen for the polyester.
The result for cotton is shown in Figure 19, where the pull-out force is
shown in the first bar for each sample. The second bar is the force for both
the pull-out force and the force were the yarn broke. There were no
significant differences for a lower force between the treated and untreated
samples. The cotton treated with 0.2 w% PEG 4000 had significant higher
friction than the untreated sample. The complete ANOVA and Tukey test
are presented in Appendix III. In Appendix VI, the force for all cotton
samples are in Table 22; those were the yarn broke are marked.
37
Figure 19. Average force for the pull-out test of cotton fabrics untreated and treated with
different concentration of PEG 4000 and glycerol. The first bar of each sample is the
pull-out force and the second both the pull-out force and the force for the yarn strength.
With error bars for the standard deviation. For sample CO 0.1 w% PEG 4000 no yarns
did break.
In Figure 20, the result of the pull-out test for polyester fabrics is presented.
The lowest values were obtained from the fabric treated with PEG 4000, and
the force is decreasing with increased concentration. The complete ANOVA
with Tukey test is found in Appendix III. For the fabric treated with 0.2 w%
PEG 4000 and 0.71 w% PEG 4000 there was a significant difference from
the untreated fabric, see Table 13 for adjusted p-values from the Tukey test.
Figure 20. Average force for the pull-out test of polyester fabrics untreated and treated
with different concentration of PEG 4000 and glycerol. With error bars for the standard
deviation.
0
0.5
1
1.5
2
2.5
3
3.5
4
4.5
CO unt CO 0.1 w%PEG 4000
CO 0.2 w%PEG 4000
CO 0.29 w%PEG 4000
CO gly
Pull-out test cotton
0
1
2
3
4
5
6
unt 0.1 w% PEG
4000
0.2 w% PEG
4000
0.71 w% PEG
4000
glycerol
Pull-out test polyester [cN]
38
Table 13. Adjusted p-values from Tukey Pairwise Comparisons between the untreated
polyester fabric and treated with different concentration of PEG 4000 and glycerol.
Treatment Adjusted p-value
0.1 w% PEG 4000 0.169 -
0.2 w% PEG 4000 0.027 +
0.71 w% PEG 4000 0,001+
1 w% glycerol 0.454 -
For polycotton, the results are presented in Figure 21, where the pull-out
force is shown in the first bar for each sample. The second bar is the force
for both the pull-out force and the force were the yarn broke. There was no
significantly lower force compared to the untreated. The samples treated
with 0.2 w% and 0.5 w% had significantly higher force than the untreated.
In Appendix VI, the force for all polycotton samples are in Table 23; those
were the yarn broke are marked.
Figure 21. Average force for the pull-out test of polycotton fabrics untreated and treated
with different concentration of PEG 4000 and glycerol. First bar of each sample is the
pull-out force and the second both the pull-out force and the force for the yarn strength.
The first bar for polycotton sample treated with 0.5 w% PEG 4000 have no error bar
since it is only one sample that did not break during testing.
SHREDDED MATERIAL: 5.2.2.
The shredded material was analysed, and the fibre length was measured.
Attempts were made to process the fibres into yarn by carding, drawing and
rotor spinning. The produced yarns were analysed, and tenacity was
measured.
0
1
2
3
4
5
6
7
COPES unt COPES 0.1 w%PEG 4000
COPES 0.2 w%PEG 4000
COPES 0.5 w%PEG 4000
COPES gly
Pull-out test polycotton
39
ANALYSIS OF SHREDDED MATERIAL 5.2.2.1.
An analysis was done on the shredded material to estimate levels of neps
and unopened threads, examples are shown in Figure 22 a and b. Fibres that
melted during shredding were found in the untreated polyester, and the ones
treated with glycerol, see Figure 22 c. The results for neps and unopened
threads in 0.25 g fibre are in Table 14.
Figure 22. a) Neps b) Unopened threads c) Melted fibre during shredding from untreated
PET (the bars are 1 mm apart).
Table 14. Number of neps and unopened threads in a 0.25 g fibre.
Sample Weight Neps Unopened
threads
Weight of
neps and
threads
% of 0.25 g
that was neps
and threads
CO untreated 0.25 91 194 0.058 23.2
CO 0.1 w%
PEG 4000
0.25 80 144 0.053 21.2
CO 0.29 w%
PEG 4000
0.25 59 116 0.046 18.4
CO glycerol 0.25 73 88 0.0430 17.2
PET untreated 0.25 386 299 0.111 44.4
PET 0.2 w%
PEG 4000
0.25 234 269 0.103 41.2
PET 0.71 w%
PEG 4000
0.25 154 129 0.055 22
PET glycerol 0.25 475 127 0.076 30.4
CO/PET
untreated
0.25 450 137 0.056 22.4
CO/PET 0.1
w% PEG 4000
0.25 268 197 0.056 22.4
CO/PET 0.5
w% PEG 4000
0.25 372 153 0.046 18.4
CO/PET
glycerol
0.25 276 133 0.042 16.8
a b c
40
FIBRE LENGTH MEASUREMENT 5.2.2.2.
The results for the fibre length of the reclaimed fibre from the shredded
material are in Table 15. In Appendix VIII are pictures of all samples
prepared for fibre length measurement.
Table 15. Mean Fibre length and comparison with the initial length of warp and weft and
the difference to the untreated sample.
Sample Fibre
length
[mm]
Fibre
length
drop
compared
with weft
[mm]
% of
initial
fibre
length
weft
Fibre
length
drop
compared
with warp
[mm]
% of
initial
fibre
length
warp
%
difference
to the
untreated
sample
CO
untreated
9.1 -18.5 33 -11.5 44 -
CO 0.1
w% PEG
4000
11.9 -15.7 43 -8.7 58 31
CO 0.29
w% PEG
4000
13.4 -14.2 49 -7.2 65 47
CO
glycerol
8.5 -19.1 31 -12.1 41 -7
PET
untreated
7.8 -20.2 28 - - -
PET 0.2
w% PEG
4000
15.1 -12.9 54 - - 94
PET 0.71
w% PEG
4000
17.2 -10.8 61 - - 121
PET
glycerol
10.2 -17.8 36 - - 31
CO/PET
untreated
9.4 -19.4 33 -16 37
CO/PET
0.1w%
PEG 4000
12.9 -15.9 45 -12.5 51 38
CO/PET
0.5 w%
PEG 4000
13.1 -15.7 45 -12.3 52 40
CO/PET
glycerol
7 -21.8 24 -18.4 28 -25
The untreated cotton sample had a mean fibre length of 9.1 mm and
compared to the initial length of the weft fibres, that is a fibre length drop of
18,5 mm and 11.5 mm compared to warp. Cotton treated with 0.1 w% PEG
4000 had a mean fibre length of 11.9 mm, and that was 31% longer than the
untreated. Treated with 0.29 w% the mean fibre length was 13.4 mm, and
that was 47 % longer. The mean fibre length for cotton treated with glycerol
41
was 8.5 mm and, which was -7 % shorter than the untreated. The cotton
mean fibre length is presented in Figure 23.
Figure 23. Fibre length for cotton samples.
For polyester, the mean fibre length was 7.8 mm, and that was a fibre length
drop of 20.2 mm compared to the mean fibre length of the weft. For the
polyester treated with PEG 4000, the fibre length for 0.2 w% was 15.1 mm,
94 % longer than the untreated, and for 0.71 w%, the fibre length was 17.2
mm, which is 121 % longer than the untreated. The mean fibre length for
polyester treated with glycerol was 10.2, compared with untreated that was
31 % longer. The polyester mean fibre length is presented in Figure 24.
Figure 24. Fibre length for polyester samples.
For the polycotton, the mean fibre length of the untreated was 9.4 mm, a
fibre length drop of 19.4 mm compared to the mean initial length of weft,
and 16 mm compared to warp. For the polycotton treated with PEG 4000,
0
2
4
6
8
10
12
14
16
18
20
Cotton
Fibre length cotton
Untreated
0.1 w% PEG
4000
0.29 w% PEG
4000
1% Glycerol
0
2
4
6
8
10
12
14
16
18
20
Polyester
Fibre length polyester
Untreated
0.2 w% PEG
4000
0.71 w% PEG
4000
1% Glycerol
42
the mean fibre length was 12.9 mm for 0.1 w% , 38 % longer compared the
untreated. For 0.5 w%, it was 13.1 mm, which was 40 % longer. The
polycotton fabric treated with glycerol had a mean fibre length of 7 mm,
which was -25 % compared to the untreated. In Figure 25, the mean fibre
length is presented for the polycotton samples.
Figure 25. Fibre length for polycotton samples.
For comparison and internal control of the method, virgin cotton fibres were
analysed with the same method and sample size. The results for virgin
cotton were 27 mm. The virgin cotton was used in the pre-study and also
blended with the reclaimed fibre for yarn production and had a known
average fibre length of 26 mm.
CARDING OF SHREDDED MATERIAL 5.2.2.3.
The reclaimed fibres had to be able to form webs during carding to be
processed further. A random sample of 12 tufts of 2.5 g, totally 30 g, was
taken from each shredded sample. Table 16 shows the result of the carding.
For cotton, all samples formed webs. Untreated polyester were the only
polyester samples that did not form a web. None of the polycotton samples
could be carded.
For sliver production, carded webs of 25 g and 20 g were made from of the
shredded material that could be carded. Also, carded webs were made of
blends of shredded material and virgin cotton fibres.
0
2
4
6
8
10
12
14
16
18
20
Polycotton
Fibre length polycotton
Untreated
0.1w% PEG
4000
0.5 w% PEG
4000
1% Glycerol
43
Table 16. Carding and drawing of the random sample of 30 g of the reclaimed fibres.
Sample First carding Second carding Sliver
CO untreated
formed web
formed web Possible to make a
sliver
CO 0.1w% PEG
4000
formed web formed web Possible to make a
sliver
CO 0.29 % PEG
4000
formed
web
formed web Possible to make a
sliver
CO
glycerol
formed web formed web Possible to make a
sliver
PET untreated did not form web did not form web -
PET 0.2w% PEG
4000
Formed web Formed web Possible to make a
sliver
PET 0.71 w%
PEG 4000
Formed web formed web Possible to make a
sliver
PET
glycerol
Formed web Formed web Possible to make a
sliver
CO/PET
untreated
did not form web did not form web -
CO/PET 0.1w%
PEG 4000
did not form web
did not form web -
CO/PET 0.5 w%
PEG 4000
did not form web
did not form web -
CO/PET
glycerol
did not form web
did not form web -
SLIVER 5.2.2.4.
To achieve a more gentle drawing, the sprockets were changed to alter both
the total draft in the drawing frame and change the ratio between the pre-
draft and main draft, see Figure 15 on page 30. The total draft was
decreased. The pre-draft was increased, and the main draft decreased, which
means that the total draft is divided between the pre-draft and main draft.
The settings used gave approximately a draw of two times the initial length.
The slivers were only drawn once. The setting used was A:32, B:20, C:52
and D:20 and were used for the production of all slivers. Test for finding a
drawing that suits the reclaimed fibres was performed using the setting for
the sprockets as in Table 24 in Appendix VI.
All carded webs of reclaimed fibres in Table 16 were drawn into slivers.
Also, the carded webs prepared of 20g and 25 g shredded material were
drawn into slivers. For the blending reclaimed fibres with virgin cotton, the
sample size of 18 g was selected. All prepared blended webs were drawn
into slivers. All slivers produced are listed in Table 17.
44
Table 17. Samples drawn into slivers and their weight before carding and the
approximate tex number.
Samples that formed
web 100% reclaimed
fibres
30g 25g 20g
CO untreated 8000 tex 6900 tex 5300 tex
CO 0.1 w% PEG 4000 9000 tex 6400 tex 5000 tex
CO 0.29 w%PEG 4000 7500 tex 6250 tex 5100 tex
CO glycerol 8000 tex 6500 tex 4300 tex
PET 0.2 w% PEG 4000 8000 tex 6700 tex 4600 tex
PET 0.71 w% PEG 4000 7700 tex 6900 tex 5150 tex
PET glycerol 7000 tex 6200 tex 4900 tex
Sample of blend of
reclaimed fibres (RF)
and new virgin cotton
fibres
9 g RF 9 g
virgin CO
8 g RF 8 g virgin
CO
10 g RF 10 g
virgin CO
CO untreated 6400 tex 4800 tex
CO 0.1 w% PEG 4000 5700 tex 7000 tex
CO 0.29 w% PEG 4000 6250 tex
CO glycerol 5600 tex
PET 0.2 w% PEG 4000 5600 tex
PET 0.71 w% PEG 4000 5400 tex
PET glycerol 5900 tex
YARN PRODUCTION 5.2.2.5.
In Table 18, are the rotor spinning settings for the yarn produced and the
settings that were tested but did not work for some of the reclaimed fibres.
Yarn counts were tried from 100 tex to 140 tex and alpha from 150 to 220.
Settings that worked for the slivers produced a yarn with an expected linear
density of approximately 120 tex and had an expected yarn alpha of 220. In
Table 18, successful means that the yarn was produced without breaks.
45
Table 18. Yarn produced and settings from rotor spinning. Successful means that the
yarn was produced without breaks.
Material Sliver
[Ktex]
total
draft
Expected
yarn count
[tex]
alpha Delivery
[m/min]
Yarn
produced
CO 0.1 w%
PEG 4000
6.40 53 121 220 79 Successful
CO untreated 6.90 57 121 220 79 Successful
CO 0.29 w%
PEG 4000
6.25 52 120 220 79 Successful
CO glycerol 6.50 54 120 220 79 Not
possible
8g CO
untreated
8g Virgin CO
4.80 43 112 170 98 Successful*
9g co 0.1w%
PEG 4000, 9g
Virgin CO
5.70 47 121 170 102 Successful*
PET 0.2 w%
PEG 4000
6.70 55 122 220 79 Problem
producing
yarn
PET 0.71 w%
PEG 4000
5.20 43 121 220 79 Successful
PET glycerol 6.20 51 122 220 79 Not
possible
9 g PET 0.2
w% PEG 4000
+ 9g Virgin
CO
5.60 46 122 220 79 Successful
9 g PET 0.71
w% PEG 4000
+ 9g NF CO
6.90 57 121 220 79 Successful
100% virgin
cotton
5.10 42 121 220 79 Successful
*Lower alpha, yarn produced during test of different settings
46
LINEAR DENSITY OF ROTOR SPUN YARN 5.2.2.6.
The linear density in tex of the yarn produced is presented in Table 19. The
linear density is used for testing the strength of the yarns.
Table 19. Linear density of rotor spun yarns.
Sample Linear density [tex]
CO untreated 99 tex
CO 0.1 w% PEG 4000 98 tex
CO 0.29 w% PEG 4000 92 tex
8 g CO untreated + 8 g Virgin CO 91 tex
9 g CO 0.1 w% PEG 4000 + 9 g virgin CO 114 tex
PET 0.2 w% PEG 4000 96 tex
PET 0.71 w% PEG 4000 104 tex
9 g PET 0.2 w% PEG 4000 + 9 g virgin CO 123 tex
9 g PET 0.71 w% PEG 4000 + 9 g virgin CO 113 tex
Virgin CO, reference yarn 109 tex
After the yarn was washed, the linear density was calculated. The results are
presented in Table 20. The linear density of the washed yarn was used for
testing the strength of the yarns after the treatment was removed. Note that
there are different samples in Table 19 and 20 and not the same before and
after washing. The shrinkage was not measured.
Table 20. Linear density of rotor spun yarns after washing.
Sample Linear density after
washing [tex]
CO untreated 97 tex
CO 0.1 w% PEG 4000 98 tex
CO 0.29 w% PEG 4000 109 tex
8 g CO untreated + 8 g Virgin CO 99 tex
9 g CO 0.1 w% PEG 4000 + 9 g virgin CO 104 tex
PET 0.71 w% PEG 4000 99 tex
9 g PET 0.2 w% PEG 4000 + 9 g virgin CO 107 tex
9 g PET 0.71 w% PEG 4000 + 9 g virgin CO 107 tex
Virgin CO, reference yarn 104 tex
47
TENSILE TEST OF PRODUCED YARN 5.2.2.7.
Figure 26, shows the tenacities from the tensile test of the rotor spun yarns
with error bars for standard deviation. ANOVA and Tukey test is in
Appendix IV. For reclaimed cotton, the sample treated with 0.1 w% PEG
4000 and the untreated had approximately the same tenacity. The sample
treated with 0.29 w % PEG 4000 had a lower tenacity, but no difference is
significant between the reclaimed cotton samples, the reclaimed cotton is
the red bars in Figure 26. There were no significant differences between the
yarns spun from reclaimed cotton only and the ones spun of reclaimed
cotton blended with virgin cotton. For the reclaimed polyester yarn, the
sample treated with 0.71 w% PEG 4000 produced a significant stronger yarn
than the sample treated with 0.2 w% PEG 4000, the reclaimed polyester
samples are the green bars in Figure 26. Both the yarn made from reclaimed
polyester blended with virgin cotton were significantly stronger than the
yarn made from polyester treated with 0.2 w% PEG 4000. All samples made
from reclaimed fibres were significantly weaker than the yarn made from
virgin cotton fibres, the yarn from the virgin cotton is the blue bar in Figure
26.
Figure 26. Tenacity for rotor spun yarns with error bars for standard deviation. Under
each bar is the sample name.
All yarns treated with PEG 4000 had an increase of tenacity after washing.
Figure 27 show comparison between rotor spun yarns before and after
washing. However, only the yarn made from the cotton treated with 0.29
w% PEG 4000 had a significant increase in tenacity compared to before
washing. Further, the yarn made from the cotton treated with 0.29 w% PEG
0
2
4
6
8
10
12
14
16
CO
UNT
CO 0.1
w%
PEG
4000
CO
0.29
w%
PEG
4000
8g CO
UNT+
8g vCO
9g CO
0.1 w%
PEG
4000 +
9g vCO
PET 0.2
w%
PEG
4000
PET
0.71
w%
PEG
4000
9g PET
0.2 w%
PEG
4000 +
9g vCO
9g PET
0.71
w%
PEG
4000 +
9g vCO
virgin
CO ref.
Tenacity rotor spun yarns [cN/tex]
48
4000 was significantly stronger than both the yarns made from reclaimed
cotton fibres blended with virgin cotton. The complete ANOVA and Tukey
test is presented in Appendix VI. For the polyester yarns, there were no
significant differences after washing. The yarn of reclaimed fibres with the
highest tenacity was the washed yarn made from polyester treated with 0.71
w% PEG 4000. The second highest tenacity had the washed yarn made from
cotton treated with 0.29 % PEG 4000. The virgin cotton references yarn
before and after washing was significantly stronger than the yarns of
reclaimed fibres.
Figure 27. Tenacity for rotor spun yarns before and after washing with error bars for
standard deviation. The bar to the left is without washing (same as in Figure 26) and to
the right is the washed sample.
VISUAL ANALYSIS OF THE ROTOR SPUN YARNS 5.2.2.8.
In Appendix V are all the rotor spun yarns presented. All three yarn of
reclaimed cotton had irregularities of thickness and neps in them. The two
yarns of reclaimed cotton blended with virgin cotton had neps and
irregularities of thickness. The blended yarn of reclaimed cotton hade more
neps than the of only reclaimed cotton The yarn of polyester treated with
0.71 w% PEG 4000 had a more even appearance, less thick spots and fewer
neps than the yarn treated with 0.2 w% PEG 4000. The two yarns of
reclaimed polyester blended with cotton were more similar in apparence.
The virgin cotton reference yarn was the most even in thickness.
0
2
4
6
8
10
12
14
16
CO UNT CO 0.1 w%
PEG 4000
CO 0.29
w% PEG4000
8g CO
UNT+ 8gvCO
9g CO 0.1
w% PEG4000 + 9g
vCO
PET 0.71
w% PEG4000
9g PET 0.2
w% PEG4000 + 9g
vCO
9g PET
0.71 w%PEG 4000
+ 9g vCO
virgin CO
ref.
Yarn tenasity before and after washing
49
DISCUSSION 6.It was at a late stage in this study discovered that what was thought to be
pure polyester fibres were, in fact, a bicomponent polyester and this was
also confirmed by Raman spectroscopy. Figure 28 in Appendix VI shows
the graphs of the bicomponent polyester and polyester from the fabric.
Since the sheath of the fibres was polyester with low melting temperature
and the core polyethene terephthalate, then the fibre surface that is the part
that will be affected by the conditioner. This means that the effect of the
conditioners on polyester are not confirmed by the test on the carded webs.
It is not certain that the effect on the bicomponent polyester is the same as it
would have been on pure polyethylene terephthalate staple fibres.
Tests were made on another polyester, Trevira 290 that is intended to be
used for nonwovens. However, the results were confusing since the friction
was increasing. An explanation for the results was that the polyester might
contain some kind of finish and it was later confirmed by the manufacturer
that it, in fact, did contain spin finish that could not be fully removed. It was
neither possible to test on any other polyethene terephthalate fibres as such
fibres were not available, nor to order in time. Since the effect could not be
tested on fibres, it had to be tested directly on the treated fabrics. Testing
directly on the fabric could make the further research on this subject simpler
when both the testing and shredding is done on the same material. First, the
tensile strength of the yarns from the polyester fabric was tested but the
results did not show any significant effects of the conditioning treatment
with PEG 4000 and only in weft direction for the glycerol treatment.
Guidance for the conditioner selection could not be attained by the yarn
tensile test in this way. The explanation could be that the conditioner is
mostly on the surface of the yarn. Since the result did not give sufficient
results, the other treated samples of cotton and polycotton were not tested.
The yarn from all untreated fabric was tested, and the warp yarn for
polyester and polycotton were significantly stronger than their weft.
To find a test that is more similar to what actually happens in the shredding
machine where the fabrics are ripped apart different methods were
considered. There is standard for seam slippage, and a standard method
would, of course, be preferable. However, the test of pull-out resistance
from a singular yarn from fabric was chosen due to the similarities with the
actual shredding process. With the method, it is also possible to distinguish
between static and dynamic friction as with the novel method for interfibre
friction in this thesis. There is no standard method for pull-out test nor any
frequently used test equipment or sample preparation procedure. Because of
this, a method was developed from the literature research. In the literature,
there was also an article discussing the pull-out force for polyester, and it
also tested polyester treated with softners, which have similarities with the
50
pull-out test in this thesis. Both the conditioners and softners lower the
friction.
The results from the pull-out test for cotton fabric did not give any result of
that the friction was significantly lowered. The yarn did break before it was
completely pulled out and that means that the true pull-out is higher than
what could be read from the result. For cotton, a smaller test size and gauge
length would probably work better. The samples were yarn broke most time
also had the highest friction, and the samples with the lower friction had less
yarn broken. For polyester, the pull-out test worked well, and no samples
broke. The pull-out force was significantly lower for the samples treated
with 0.2 w % and 0.71 w % PEG 4000. Those were also the concentrations
used for the fabrics for shredding, and it was possible to rotor spin yarn of
both of them, and they hade longer mean fibre length than the untreated. For
the polycotton, there were also problems with the yarn breaking. And it also
showed that the treatment increased the friction. For polycotton, it might
also be an idea to test in a different sample size. For all pull-out test were
only tested on the weft, it would, of course, be relevant to also test in the
warp direction. Weft direction was chosen since all fabric had staple fibres
in the weft. The pull-out test for the polyester untreated and treated with
conditioners have the similar behaviour as in the article by Bilisik (2011)
were the polyester treated with softener had a lower force than untreated.
One problem is achieving accurate application of the conditioner.
Application by hand spraying comes with a risk of the uneven distribution
of conditioner. Application by foulard is only possible for fabrics, and
therefore it worked well in this research but will not in a line for recycling
of various textiles. A solution for industrial scale processes would be
spraying with controlled distribution, which probably will work well for
both post-consumer textiles in pieces or pre-consumer fabrics scraps.
The fabrics were cut into smaller pieces before shredding in the cutting
machine that was not working properly and had to receive maintenance
halfway through the material. This could, of course, have influenced the
material since the fabric could possibly be unnecessarily damaged in the
cutter but there is no way of testing if it in fact did. For research purpose, it
could be better to have all fabric cut into pieces with the same size. As
Wanassi, Azzouz, & Hassen (2016) showed in their research, the initial
length of the material and the number of shredding cycles affect the length.
Furthermore, the length of the saw teeth could also contribute to short
fibres; here there were 4 mm. The shredding of polyester could possibly
have benefited from higher air humidity in the room or that a small amount
of water would be sprayed onto the fabric pieces due to static electricity
during the process.
51
Visual analysis of the samples showed that all of the polycotton samples had
a large number of neps. Neps are naturally occurring in cotton fibres and can
form in the mechanical recycling of all the materials due to the harsh
process and friction. Also, the untreated polyester sample had a large
number of neps. The neps were lower for all samples treated with PEG 4000
and for cotton and polyester the highest concentrations of PEG 4000 had the
lowest amount of neps. All the cotton samples had a lower amount of neps
than the other materials. Unopened threads show how well the material was
shredded. Of the unopened threads that were found in this analysis, some
might have opened later in the carding stage. In all the polyester samples
there were more unopened threads, and there was a large number of
multifilament warp threads, who had more crimp and could easily be
distinguished from the weft threads. It is very probable that the
multifilament in the polyester warp had a negative effect on the number of
unopened threads and the shredding of the fabric overall since the
multifilament warp was much stronger than the weft. The friction build-up
generated during shredding made the untreated polyester and treated with
glycerol melt. This was not seen for polyester samples treated with PEG
4000.
All samples treated with PEG 4000 had a higher mean fibre length
compared to untreated, and the fibre length was increasing with a higher
concentration of PEG 4000. The cotton and polycotton sample had a lower
mean fibre length than the untreated. For the polyester, the mean fibre
length was a bit longer than the untreated but not as long as the ones treated
with PEG 4000.
The reason why the reclaimed polycotton fibres were not able to be
processed further is probably that the fibres are too short. The mean fibre
length is comparable with the cotton samples but the friction is lower for the
polyester in general, and that is probably why the cotton could be carded
and not the polycotton. It is not possible in this thesis to distinguish between
the fibre length of the cotton and the polyester in the polycotton material.
But with further development of the image analysis of fibre length, it might
be possible to distinguish between the fibres and measure their length
separately in a sample. The effect of the PEG 4000 had a positive outcome
on the mean fibre length, but the concentration might not be optimal. It is
also possible that the conditioner does not work for polycotton blends since
the conditioner has a different effect on the fibres. The friction and strength
are also very different for the fibres. The strength of the polyester fibres
might affect the shredding process negatively, and the low polyester friction
could have affected the further processing. The treatment with PEG 4000
was much more effective on the polyester fibres than on the cotton. The
52
polycotton might need to be separated before recycling; if the cotton was
dissolved, then the polyester could be treated with PEG 4000.
All the reclaimed fibres of polyester and cotton except the untreated
polyester could be carded into a web. None of the polycotton samples could
be carded into a web. To be able to form web both fibre length but also
friction between the fibres are needed. All samples that were unable to form
a web could not be processed further into slivers or yarns and was therefore
excluded. The fibres that could form web were drawn into slivers. Since the
drawing is a crucial step and that drawing the fibres too much will separate
the fibres and give a sliver with gaps between larger chunks of fibres the
drawing had to be gentler. The drawing frame was remodelled with new
sprockets and chains to give a more gentle drawing. This gave a rather even
sliver that could be tested in the next step that was yarn spinning. For the
slivers of blends, the same amount of reclaimed fibres and with virgin
cotton was mixed in the carding machine. Due to fibre loss in the carding
machine, which probably was more from the reclaimed fibres, it was not
possible to know the exact proportions of fibres in the finished yarn.
Slivers in three different thickness were made since it was not possible to
determine beforehand which thickness would be most suited for rotor
spinning with reclaimed fibres. Normally, slivers of 5000 - 6000 tex is used.
But it was not known how much material would be sorted away by the
opening roller or what linear density of the sliver that was optimal for
spinning a yarn of short reclaimed fibres. What would have been good if it
had been done is to weight the trash that was collected in the box under the
rotor to see how much was sorted out from the sliver. But this was thought
of after the spinning. The whole sliver was not always processed either, and
that could complicate calculating the waste. Also, the staring of rotor
spinning generates waste. A certain technique is required to start the rotor
spinning, and that usually took a couple of tries before the machine spun and
winded the yarn properly.
The rotor spinning machine only had one 40 mm rotor, which limited the
yarn count that could be produced. A rotor of another shape or a larger rotor
could have produced a coarser yarn that might be a better option for
producing a stronger and more even yarn of the reclaimed fibres. The time
was also limited, and the process parameters could probably have been
optimized further. The alpha could perhaps have been lower for some of the
material, but there was no time to test that, and the settings that finally
worked were used for all materials. Also, due to time limitations, the blends
of reclaimed cotton mixed with virgin cotton were only ones spun and that
in the test phase of the rotor spinning there was no time to test the rest of the
blends. The polyester and cotton treated with glycerol were not spinnable,
53
and the two blends with virgin cotton were therefore also excluded from
spinning.
The actual yarn count for the produced yarns did differ from the expected;
this could be due how much material the opening roller in the rotor spinning
machine discarded as waste and also that the tex value of the slivers was
calculated approximately.
The produced rotor yarns made of reclaimed fibre from fabric treated with
PEG 4000, had an increase in tenacity after washing. However, it was only
significant for cotton treated with 0.29 w% PEG 4000. The fact the yarns
were stronger after washing means that the treatment with PEG 4000 affects
the yarn tenacity. Since PEG 4000 is water-soluble, it is easy to wash away.
Glycerol was not a suitable treatment for cotton, polyester or polycotton.
The fibre length for cotton and polycotton were shorter for samples treated
with glycerol than the untreated. Also, the number of neps was very high for
polyester and polycotton.
As mentioned, the fabrics treated with the higher concentration of PEG 4000
and glycerol was treated by another student, Catherine Namuga, and with a
different application method. This might have affected the results. Also, the
results from testing on fibres in Namugas (2017) thesis was not verified in
this work. The results from testing on fibres were not the same. She also had
a problem with the higher concentration, 0.71 w%, of PEG 4000 for
polyester that could not be drawn and therefore not spun and it is unclear
why it was chosen for the fabrics. Also, she also might have used the
bicomponent polyester and not pure polyester for her test on fibres.
One thing that could have an influence on the shredding process and was not
investigated was the twist of the yarns in the fabric. Accordingly to Furter,
and Meier (2009) the twist determinate the yarn strength. The tensile
strength of the yarns from the fabric showed that both the polyester and
polycotton had stronger warp than their weft. When it comes to the
polyester, this could be explained by it being multifilament and not staple
fibres as in the weft. But for the polycotton when the linear density was
similar between warp and weft, a higher twist for the warp yarn could
contribute to the strength.
All conditioners in this thesis are used because they are environmentally
friendly and are used in low concentrations.
It could be argued that is not sustainable to shred new unused fabric.
However, the result of this thesis could help develop the recycling process
and improve mechanical recycling. By improving the process, the fibre
would have more fibre length preserved during shredding, which means
54
longer fibres. Fibres that are longer can be processed into higher quality
applications. This means that the value of the waste would be higher and
that will make recycling more profitable.
55
CONCLUSIONS 7.The conditioner PEG 4000 did lower the friction between polyester fibres.
The results from the pull-out test showed that the friction was lowered and
the increased fibre length is another indication of that. However, finding the
ideal concentrations have to be investigated further.
The mean fibre length was longer for all materials treated with PEG 4000,
and the mean fibre length increased with the concentration of PEG 4000.
The mean fibre length for cotton and polycotton treated with glycerol was
lower than for the untreated samples, for polyester it was higher than the
untreated but lower than the ones treated with PEG 4000. For cotton, the
best result was for the treatment of 0.29 w% PEG were the fibres had almost
50 % longer mean fibre length than untreated. The best result for polyester
was treated with PEG 4000, which had a mean fibre length that was 120 %
higher than for untreated. Polycotton had almost 40 % longer mean fibre
length compared with untreated for both of the treatments of PEG 4000.
The overall quality of the reclaimed polyester fibres was better for the fibres
from fabric treated with PEG 4000 compared with the untreated and the
ones treated with glycerol. For fibres of polyester treated with PEG 4000 the
average fibre length was longer, the neps counts were lower, there were no
melted fibres, and it was possible to card, draw to a sliver, and rotor spin
into yarn. The shredded material from cotton also had a lower amount of
neps for the treated with PEG 4000, but the neps were much lower in cotton
overall. All polycotton samples had a high amount of neps.
It is not possible to say that the results from the test on fibres are applicable
to woven constructions. First, there is the problem that the test for polyester
was done with the wrong material, and PEG 4000 seems to have had the
biggest effect on polyester. None of the results from the fibre test in the pre-
study for bicomponent polyester, and therefore also the results for the blend
with cotton, can be used. The cotton fibres test and pull-out test on fabrics
do not show the similar tendency, and more tests are needed. For polyester
the pull-out test has similar results as the test performed on the actual
shredded material, the highest concentration of PEG 4000 gave the best
results. For polycotton, there was a big problem with samples where the
yarn broke before the yarn was completely pulled. The conclusion is that
pull-out test is applicable for testing friction for different conditioners, but
the sample size has to be modified so that the pull-out force is less than the
yarn strength.
It was possible to rotor spin yarns out of 100% reclaimed fibres from cotton
fabrics that were treated with PEG 4000. It was also possible to spin yarn
from reclaimed fibres from untreated cotton fabric. It was possible to rotor
spin yarns out of 100% reclaimed fibres polyester fabrics that were treated
56
with PEG 4000. The reclaimed fibres from untreated polyester were not
possible to card into a web and therefore not possible to process further into
yarn. The reclaimed fibres from cotton fabric and polyester fabric treated
with glycerol were possible to be carded and drawn, but not rotor spun.
None of the reclaimed fibres from polycotton fabric was possible to card.
For cotton, PEG 4000 gave a longer mean fibre length, and the strength of
the rotor spun yarn was stronger for the treated fibres, after washing away
the treatment, than for the untreated. PEG 4000 was a very good treatment
for polyester and gave good results on cotton but did not work on
polycotton. For polycotton, the fibre length was longer for the reclaimed
fibres from treated fabrics with PEG 4000 compared to untreated. But
nevertheless, none of the samples could be carded. Glycerol was not a
suitable conditioning treatment for any of the tested materials, cotton and
polycotton had shorter fibre length than untreated, and none of the shredded
material treated with glycerol was possible to spin a yarn of.
FUTURE RESEARCH 7.1.The concentrations of PEG 4000 for polyester have to be tested further to
find the concentration where the friction is the lowest, the reclaimed fibres
the longest and still possible to process into a yarn. After the concentrations
are optimised, it would be very interesting to test the effect of PEG 4000 on
polyester post-consumer textiles.
Other conditioners than PEG 4000 for cotton should be investigated, even if
it gives good results for cotton it is not as good as for polyester. The
polycotton fabric perhaps needs to be separated before; if the cotton is
dissolved, then the polyester could be treated with PEG 4000 and shredded.
Continue the development of the pull-out test so the friction could be tested
directly on fabrics. This method could also be used to optimize the
concentrations of PEG 4000 and other conditioners.
Continue the development of the image analysis of fibre length for samples
of blended material; it could be possible to distinguish between the fibres
and measure their length separately.
The article by Bilisik (2011) shows that the structure of the fabric is
important for friction. In Aronsson (2017) both the degree of wear but also
fabric type are factors when it comes to recycling. More research is needed
on the impact of the fabric structures on properties of the shredded material.
And also more research is needed to investigate the recyclability of ring and
rotor spun yarns with different amount of twist.
57
There is a lot that needs further research when it comes to the shredding
process, which was not investigated in this work. In Wanassi, Azzouz and
Hassen (2016) they tested a number of shredding cycles and different length
of the yarn that was shredded. This would be interesting to continue with
fabric and with a shredding machine instead of a Shirley Analyzer. Also,
compare different shredding machines with a different number of cylinders
and different sizes of the saw teeth. The shredding could benefit from air
humidity or added water. It is probably better for research purposes to have
the fabric cut into pieces of the same size before shredding than to use a
cutter. This will give a more accurate analysis of the fibre length drop and
its reason. The fibre length could never be longer than the initial length of
the fibres of the yarns in the textiles or the size of the pieces the textile is cut
prior to shredding.
There is a lot of material lost in both the shredding process and carding
process of reclaimed fibres. A process to determine the yield of shredded
material and different losses during the process should be developed. The
carding process for shredded material could be developed further if there is
a possibility to limit the fibre length drop in the carding process. Also, using
a carding machine that could sort out the shortest fibres would be better. The
sorting could also help to divide the fibres that could be respun into yarn and
those that cannot, but they have other possible uses as for example chemical
recycling or reinforcement in composites. Also. the material lost in the
shredding process might also be possible to use.
The rotor spinning process for reclaimed fibres could be optimized further.
It would also be interesting to measure the twist count of the produced yarn
of reclaimed fibres. And also to test what actually could be produced by
these yarns.
58
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65
APPENDIX I: ANOVA FOR CARDED WEBS
One-way ANOVA: Cotton untreated and treated with PEG 4000
Method
Null hypothesis All means are equal
Alternative hypothesis At least one mean is different
Significance level α = 0,05
Equal variances were assumed for the analysis.
Factor Information
Factor Levels Values
Factor 4 CO; CO 0.1; CO 0.2; CO 0.3
Analysis of Variance
Source DF Adj SS Adj MS F-Value P-Value
Factor 3 0,3773 0,12576 4,82 0,006
Error 36 0,9386 0,02607
Total 39 1,3159
Model Summary
S R-sq R-sq(adj) R-sq(pred)
0,161472 28,67% 22,73% 11,94%
Means
Factor N Mean StDev 95% CI
CO 10 1,7374 0,1921 (1,6338; 1,8410)
CO 0.1 10 1,4951 0,1047 (1,3915; 1,5986)
CO 0.2 10 1,5593 0,1708 (1,4558; 1,6629)
CO 0.3 10 1,6883 0,1650 (1,5847; 1,7918)
Pooled StDev = 0,161472
Tukey Pairwise Comparisons
Grouping Information Using the Tukey Method and 95% Confidence
Factor N Mean Grouping
CO 10 1,7374 A
CO 0.3 10 1,6883 A B
CO 0.2 10 1,5593 A B
CO 0.1 10 1,4951 B
Means that do not share a letter are significantly different.
Tukey Simultaneous Tests for Differences of Means
Difference of Difference SE of Adjusted
Levels of Means Difference 95% CI T-Value P-Value
CO 0.1 - CO -0,2423 0,0722 (-0,4369; -0,0478) -3,36 0,010
CO 0.2 - CO -0,1781 0,0722 (-0,3726; 0,0165) -2,47 0,083
CO 0.3 - CO -0,0491 0,0722 (-0,2437; 0,1454) -0,68 0,904
CO 0.2 - CO 0.1 0,0642 0,0722 (-0,1303; 0,2588) 0,89 0,810
CO 0.3 - CO 0.1 0,1932 0,0722 (-0,0014; 0,3877) 2,68 0,052
CO 0.3 - CO 0.2 0,1289 0,0722 (-0,0656; 0,3235) 1,79 0,297
Individual confidence level = 98,93%
One-way ANOVA: Bicomponent polyseter untreated and treated with PEG
4000
66
Method
Null hypothesis All means are equal
Alternative hypothesis At least one mean is different
Significance level α = 0.05
Equal variances were assumed for the analysis.
Factor Information
Factor Levels Values
Factor 4 BCPES, BCPES 0.1, BCPES 0.2, BCPES 0.3
Analysis of Variance
Source DF Adj SS Adj MS F-Value P-Value
Factor 3 2.0014 0.667119 127.06 0.000
Error 36 0.1890 0.005250
Total 39 2.1904
Model Summary
S R-sq R-sq(adj) R-sq(pred)
0.0724584 91.37% 90.65% 89.35%
Means
Factor N Mean StDev 95% CI
BCPES 10 1.0605 0.1170 (1.0141, 1.1070)
BCPES 0.1 10 0.6093 0.0497 (0.5629, 0.6558)
BCPES 0.2 10 0.4919 0.0405 (0.4454, 0.5384)
BCPES 0.3 10 0.5578 0.0566 (0.5113, 0.6042)
Pooled StDev = 0.0724584
Tukey Pairwise Comparisons
Grouping Information Using the Tukey Method and 95% Confidence
Factor N Mean Grouping
BCPES 10 1.0605 A
BCPES 0.1 10 0.6093 B
BCPES 0.3 10 0.5578 B C
BCPES 0.2 10 0.4919 C
Means that do not share a letter are significantly different.
Tukey Simultaneous Tests for Differences of Means
Difference SE of
Adjusted
Difference of Levels of Means Difference 95% CI T-Value
P-Value
BCPES 0.1 - BCPES -0.4512 0.0324 (-0.5385, -0.3639) -13.92 0.000
BCPES 0.2 - BCPES -0.5687 0.0324 (-0.6560, -0.4814) -17.55 0.000
BCPES 0.3 - BCPES -0.5028 0.0324 (-0.5901, -0.4155) -15.52 0.000
BCPES 0.2 - BCPES 0.1 -0.1174 0.0324 (-0.2047, -0.0301) -3.62 0.005
BCPES 0.3 - BCPES 0.1 -0.0516 0.0324 (-0.1389, 0.0357) -1.59 0.396
BCPES 0.3 - BCPES 0.2 0.0659 0.0324 (-0.0214, 0.1532) 2.03 0.195
Individual confidence level = 98.93%
One-way ANOVA: 50 % cotton and 50 % Bicomponent untreated and treated
with PEG 4000
Method
Null hypothesis All means are equal
Alternative hypothesis At least one mean is different
67
Significance level α = 0.05
Equal variances were assumed for the analysis.
Factor Information
Factor Levels Values
Factor 4 50CO50BCPES UNT, 50CO50BCPES 0.1, 50CO50BCPES 0.15,
50CO50BCPES 0.2
Analysis of Variance
Source DF Adj SS Adj MS F-Value P-Value
Factor 3 0.2381 0.07938 2.33 0.091
Error 36 1.2262 0.03406
Total 39 1.4643
Model Summary
S R-sq R-sq(adj) R-sq(pred)
0.184553 16.26% 9.28% 0.00%
Means
Factor N Mean StDev 95% CI
50CO50BCPES UNT 10 1.2897 0.0945 (1.1713, 1.4080)
50CO50BCPES 0.1 10 1.1729 0.0731 (1.0545, 1.2912)
50CO50BCPES 0.15 10 1.2280 0.1259 (1.1096, 1.3464)
50CO50BCPES 0.2 10 1.381 0.326 ( 1.262, 1.499)
Pooled StDev = 0.184553
Tukey Pairwise Comparisons
Grouping Information Using the Tukey Method and 95% Confidence
Factor N Mean Grouping
50CO50BCPES 0.2 10 1.381 A
50CO50BCPES UNT 10 1.2897 A
50CO50BCPES 0.15 10 1.2280 A
50CO50BCPES 0.1 10 1.1729 A
Means that do not share a letter are significantly different.
Tukey Simultaneous Tests for Differences of Means
Difference of Difference SE of Adjusted
Levels of Means Difference 95% CI T-Value P-Value
50CO50BCPES - 50CO50BCPES -0.1168 0.0825 (-0.3392, 0.1055) -1.42 0.498
50CO50BCPES - 50CO50BCPES -0.0617 0.0825 (-0.2840, 0.1607) -0.75 0.877
50CO50BCPES - 50CO50BCPES 0.0910 0.0825 (-0.1314, 0.3133) 1.10 0.690
50CO50BCPES - 50CO50BCPES 0.0551 0.0825 (-0.1672, 0.2775) 0.67 0.908
50CO50BCPES - 50CO50BCPES 0.2078 0.0825 (-0.0146, 0.4302) 2.52 0.074
50CO50BCPES - 50CO50BCPES 0.1527 0.0825 (-0.0697, 0.3750) 1.85 0.268
Individual confidence level = 98.93%
One-way ANOVA: 75 % cotton and 25 % bicomponent polyester untreated
and treated with PEG 4000
Method
Null hypothesis All means are equal
Alternative hypothesis At least one mean is different
Significance level α = 0.05
Equal variances were assumed for the analysis.
68
Factor Information
Factor Levels Values
Factor 4 75CO25BCPES unt, 75CO25BCPES 0.1, 75CO25BCPES 0.15,
75CO25BCPES 0.2
Analysis of Variance
Source DF Adj SS Adj MS F-Value P-Value
Factor 3 0.05242 0.01747 1.58 0.212
Error 36 0.39858 0.01107
Total 39 0.45100
Model Summary
S R-sq R-sq(adj) R-sq(pred)
0.105222 11.62% 4.26% 0.00%
Means
Factor N Mean StDev 95% CI
75CO25BCPES unt 10 1.5727 0.0921 (1.5052, 1.6402)
75CO25BCPES 0.1 10 1.5991 0.1144 (1.5316, 1.6666)
75CO25BCPES 0.15 10 1.5080 0.1043 (1.4405, 1.5754)
75CO25BCPES 0.2 10 1.5263 0.1088 (1.4589, 1.5938)
Pooled StDev = 0.105222
Tukey Pairwise Comparisons
Grouping Information Using the Tukey Method and 95% Confidence
Factor N Mean Grouping
75CO25BCPES 0.1 10 1.5991 A
75CO25BCPES unt 10 1.5727 A
75CO25BCPES 0.2 10 1.5263 A
75CO25BCPES 0.15 10 1.5080 A
Means that do not share a letter are significantly different.
Tukey Simultaneous Tests for Differences of Means
Difference of Difference SE of Adjusted
Levels of Means Difference 95% CI T-Value P-Value
75CO25BCPES - 75CO25BCPES 0.0264 0.0471 (-0.1004, 0.1531) 0.56 0.943
75CO25BCPES - 75CO25BCPES -0.0648 0.0471 (-0.1915, 0.0620) -1.38 0.522
75CO25BCPES - 75CO25BCPES -0.0464 0.0471 (-0.1731, 0.0804) -0.99 0.759
75CO25BCPES - 75CO25BCPES -0.0911 0.0471 (-0.2179, 0.0357) -1.94 0.231
75CO25BCPES - 75CO25BCPES -0.0727 0.0471 (-0.1995, 0.0540) -1.55 0.422
75CO25BCPES - 75CO25BCPES 0.0184 0.0471 (-0.1084, 0.1452) 0.39 0.979
Individual confidence level = 98.93%
One-way ANOVA: Polyester trevira 290 untreated and treated with PEG 4000
Method
Null hypothesis All means are equal
Alternative hypothesis At least one mean is different
Significance level α = 0.05
Equal variances were assumed for the analysis.
Factor Information
Factor Levels Values
69
Factor 4 PET T290 unt, PET T290 0.1, PET T290 0.2, PET T290 0.3
Analysis of Variance
Source DF Adj SS Adj MS F-Value P-Value
Factor 3 0.6827 0.22756 20.16 0.000
Error 36 0.4063 0.01129
Total 39 1.0890
Model Summary
S R-sq R-sq(adj) R-sq(pred)
0.106236 62.69% 59.58% 53.94%
Means
Factor N Mean StDev 95% CI
PET T290 unt 10 1.2172 0.1361 (1.1491, 1.2853)
PET T290 0.1 10 1.3850 0.0869 (1.3169, 1.4532)
PET T290 0.2 10 1.4910 0.0922 (1.4228, 1.5591)
PET T290 0.3 10 1.1639 0.1028 (1.0957, 1.2320)
Pooled StDev = 0.106236
Tukey Pairwise Comparisons
Grouping Information Using the Tukey Method and 95% Confidence
Factor N Mean Grouping
PET T290 0.2 10 1.4910 A
PET T290 0.1 10 1.3850 A
PET T290 unt 10 1.2172 B
PET T290 0.3 10 1.1639 B
Means that do not share a letter are significantly different.
Tukey Simultaneous Tests for Differences of Means
Difference of Difference SE of Adjusted
Levels of Means Difference 95% CI T-Value P-Value
PET T290 0.1 - PET T290 unt 0.1678 0.0475 ( 0.0398, 0.2958) 3.53 0.006
PET T290 0.2 - PET T290 unt 0.2738 0.0475 ( 0.1458, 0.4018) 5.76 0.000
PET T290 0.3 - PET T290 unt -0.0533 0.0475 (-0.1813, 0.0747) -1.12 0.678
PET T290 0.2 - PET T290 0.1 0.1059 0.0475 (-0.0221, 0.2339) 2.23 0.135
PET T290 0.3 - PET T290 0.1 -0.2212 0.0475 (-0.3492, -0.0932) -4.66 0.000
PET T290 0.3 - PET T290 0.2 -0.3271 0.0475 (-0.4551, -0.1991) -6.88 0.000
Individual confidence level = 98.93%
70
APPENDIX II: ANOVA FOR YARNS FROM FABRICS
One-way ANOVA: Tensile strength polyester weft [cN]
Method
Null hypothesis All means are equal
Alternative hypothesis At least one mean is different
Significance level α = 0.05
Equal variances were assumed for the analysis.
Factor Information
Factor Levels Values
Factor 6 PET unt, PET 0.1w% PEG 4000, PET 0.15w% PEG 4000, PET 0.2w%
PEG 4000, PET
0.71 w% PEG 4000, PET GLY
Analysis of Variance
Source DF Adj SS Adj MS F-Value P-Value
Factor 5 60797 12159 4.35 0.001
Error 114 318994 2798
Total 119 379792
Model Summary
S R-sq R-sq(adj) R-sq(pred)
52.8980 16.01% 12.32% 6.93%
Means
Factor N Mean StDev 95% CI
PET unt 20 688.1 57.3 ( 664.7, 711.6)
PET 0.1w% PEG 4000 20 670.60 39.70 (647.17, 694.03)
PET 0.15w% PEG 4000 20 691.5 62.3 ( 668.1, 715.0)
PET 0.2w% PEG 4000 20 647.05 42.15 (623.62, 670.48)
PET 0.71 w% PEG 4000 20 697.1 55.7 ( 673.7, 720.5)
PET GLY 20 638.2 56.3 ( 614.8, 661.6)
Pooled StDev = 52.8980
Tukey Pairwise Comparisons
Grouping Information Using the Tukey Method and 95% Confidence
Factor N Mean Grouping
PET 0.71 w% PEG 4000 20 697.1 A
PET 0.15w% PEG 4000 20 691.5 A B
PET unt 20 688.1 A B
PET 0.1w% PEG 4000 20 670.60 A B C
PET 0.2w% PEG 4000 20 647.05 B C
PET GLY 20 638.2 C
Means that do not share a letter are significantly different.
Tukey Simultaneous Tests for Differences of Means
71
Difference of Difference SE of Adjusted
Levels of Means Difference 95% CI T-Value P-Value
PET 0.1w% PE - PET unt -17.5 16.7 ( -66.0, 30.9) -1.05 0.900
PET 0.15w% P - PET unt 3.4 16.7 ( -45.1, 51.9) 0.20 1.000
PET 0.2w% PE - PET unt -41.1 16.7 ( -89.6, 7.4) -2.46 0.146
PET 0.71 w% - PET unt 9.0 16.7 ( -39.5, 57.4) 0.54 0.995
PET GLY - PET unt -49.9 16.7 ( -98.4, -1.5) -2.99 0.040
PET 0.15w% P - PET 0.1w% PE 20.9 16.7 ( -27.5, 69.4) 1.25 0.810
PET 0.2w% PE - PET 0.1w% PE -23.6 16.7 ( -72.0, 24.9) -1.41 0.722
PET 0.71 w% - PET 0.1w% PE 26.5 16.7 ( -22.0, 75.0) 1.58 0.611
PET GLY - PET 0.1w% PE -32.4 16.7 ( -80.9, 16.1) -1.94 0.385
PET 0.2w% PE - PET 0.15w% P -44.5 16.7 ( -93.0, 4.0) -2.66 0.092
PET 0.71 w% - PET 0.15w% P 5.6 16.7 ( -42.9, 54.0) 0.33 0.999
PET GLY - PET 0.15w% P -53.3 16.7 (-101.8, -4.9) -3.19 0.022
PET 0.71 w% - PET 0.2w% PE 50.1 16.7 ( 1.6, 98.5) 2.99 0.039
PET GLY - PET 0.2w% PE -8.8 16.7 ( -57.3, 39.6) -0.53 0.995
PET GLY - PET 0.71 w% -58.9 16.7 (-107.4, -10.4) -3.52 0.008
Individual confidence level = 99.55%
One-way ANOVA: Tensile strength for polyester warp [cN] Method
Null hypothesis All means are equal
Alternative hypothesis At least one mean is different
Significance level α = 0.05
Equal variances were assumed for the analysis.
Factor Information
Factor Levels Values
Factor 6 PET unt, PET 0.1w% PEG 4000, PET 0.15w% PEG 4000, PET 0.2w%
PEG 4000, PET
0.71w% PEG 4000, PET GLY
Analysis of Variance
Source DF Adj SS Adj MS F-Value P-Value
Factor 5 7566 1513.2 5.38 0.000
Error 114 32036 281.0
Total 119 39602
Model Summary
S R-sq R-sq(adj) R-sq(pred)
16.7635 19.11% 15.56% 10.37%
Means
Factor N Mean StDev 95% CI
PET unt 20 596.70 15.88 (589.27, 604.13)
PET 0.1w% PEG 4000 20 617.95 17.69 (610.52, 625.38)
PET 0.15w% PEG 4000 20 614.50 16.77 (607.07, 621.93)
PET 0.2w% PEG 4000 20 617.15 15.19 (609.72, 624.58)
PET 0.71w% PEG 4000 20 614.50 16.57 (607.07, 621.93)
PET GLY 20 603.00 18.29 (595.57, 610.43)
Pooled StDev = 16.7635
Tukey Pairwise Comparisons
Grouping Information Using the Tukey Method and 95% Confidence
Factor N Mean Grouping
PET 0.1w% PEG 4000 20 617.95 A
PET 0.2w% PEG 4000 20 617.15 A
PET 0.71w% PEG 4000 20 614.50 A
72
PET 0.15w% PEG 4000 20 614.50 A
PET GLY 20 603.00 A B
PET unt 20 596.70 B
Means that do not share a letter are significantly different.
Tukey Simultaneous Tests for Differences of Means
Difference of Difference SE of Adjusted
Levels of Means Difference 95% CI T-Value P-Value
PET 0.1w% PE - PET unt 21.25 5.30 ( 5.88, 36.62) 4.01 0.002
PET 0.15w% P - PET unt 17.80 5.30 ( 2.43, 33.17) 3.36 0.013
PET 0.2w% PE - PET unt 20.45 5.30 ( 5.08, 35.82) 3.86 0.003
PET 0.71w% P - PET unt 17.80 5.30 ( 2.43, 33.17) 3.36 0.013
PET GLY - PET unt 6.30 5.30 ( -9.07, 21.67) 1.19 0.842
PET 0.15w% P - PET 0.1w% PE -3.45 5.30 (-18.82, 11.92) -0.65 0.987
PET 0.2w% PE - PET 0.1w% PE -0.80 5.30 (-16.17, 14.57) -0.15 1.000
PET 0.71w% P - PET 0.1w% PE -3.45 5.30 (-18.82, 11.92) -0.65 0.987
PET GLY - PET 0.1w% PE -14.95 5.30 (-30.32, 0.42) -2.82 0.061
PET 0.2w% PE - PET 0.15w% P 2.65 5.30 (-12.72, 18.02) 0.50 0.996
PET 0.71w% P - PET 0.15w% P 0.00 5.30 (-15.37, 15.37) 0.00 1.000
PET GLY - PET 0.15w% P -11.50 5.30 (-26.87, 3.87) -2.17 0.260
PET 0.71w% P - PET 0.2w% PE -2.65 5.30 (-18.02, 12.72) -0.50 0.996
PET GLY - PET 0.2w% PE -14.15 5.30 (-29.52, 1.22) -2.67 0.090
PET GLY - PET 0.71w% P -11.50 5.30 (-26.87, 3.87) -2.17 0.260
Individual confidence level = 99.55%
One-way ANOVA: Tenacity [cN/tex] for yarns from untreated fabrics Method
Null hypothesis All means are equal
Alternative hypothesis At least one mean is different
Significance level α = 0.05
Equal variances were assumed for the analysis.
Factor Information
Factor Levels Values
Factor 6 PES weft, CO weft, CO/PES weft, PES warp, CO warp, CO/PES
warp
Analysis of Variance
Source DF Adj SS Adj MS F-Value P-Value
Factor 5 4501.3 900.260 434.14 0.000
Error 114 236.4 2.074
Total 119 4737.7
Model Summary
S R-sq R-sq(adj) R-sq(pred)
1.44003 95.01% 94.79% 94.47%
Means
Factor N Mean StDev 95% CI
PES weft 20 17.650 1.496 (17.012, 18.288)
CO weft 20 15.150 1.348 (14.512, 15.788)
CO/PES weft 20 19.400 1.603 (18.762, 20.038)
PES warp 20 33.500 1.051 (32.862, 34.138)
CO warp 20 16.250 1.585 (15.612, 16.888)
CO/PES warp 20 20.750 1.482 (20.112, 21.388)
Pooled StDev = 1.44003
73
Tukey Pairwise Comparisons
Grouping Information Using the Tukey Method and 95% Confidence
Factor N Mean Grouping
PES warp 20 33.500 A
CO/PES warp 20 20.750 B
CO/PES weft 20 19.400 C
PES weft 20 17.650 D
CO warp 20 16.250 E
CO weft 20 15.150 E
Means that do not share a letter are significantly different.
Tukey Simultaneous Tests for Differences of Means
Difference of Difference SE of Adjusted
Levels of Means Difference 95% CI T-Value P-Value
CO weft - PES weft -2.500 0.455 ( -3.820, -1.180) -5.49 0.000
CO/PES weft - PES weft 1.750 0.455 ( 0.430, 3.070) 3.84 0.003
PES warp - PES weft 15.850 0.455 ( 14.530, 17.170) 34.81 0.000
CO warp - PES weft -1.400 0.455 ( -2.720, -0.080) -3.07 0.031
CO/PES warp - PES weft 3.100 0.455 ( 1.780, 4.420) 6.81 0.000
CO/PES weft - CO weft 4.250 0.455 ( 2.930, 5.570) 9.33 0.000
PES warp - CO weft 18.350 0.455 ( 17.030, 19.670) 40.30 0.000
CO warp - CO weft 1.100 0.455 ( -0.220, 2.420) 2.42 0.160
CO/PES warp - CO weft 5.600 0.455 ( 4.280, 6.920) 12.30 0.000
PES warp - CO/PES weft 14.100 0.455 ( 12.780, 15.420) 30.96 0.000
CO warp - CO/PES weft -3.150 0.455 ( -4.470, -1.830) -6.92 0.000
CO/PES warp - CO/PES weft 1.350 0.455 ( 0.030, 2.670) 2.96 0.042
CO warp - PES warp -17.250 0.455 (-18.570, -15.930) -37.88 0.000
CO/PES warp - PES warp -12.750 0.455 (-14.070, -11.430) -28.00 0.000
CO/PES warp - CO warp 4.500 0.455 ( 3.180, 5.820) 9.88 0.000
Individual confidence level = 99.55%
74
APPENDIX III: ANOVA FOR PULL-OUT TEST
One-way ANOVA: Pull-out cotton
Method
Null hypothesis All means are equal
Alternative hypothesis At least one mean is different
Significance level α = 0.05
Equal variances were assumed for the analysis.
Factor Information
Factor Levels Values
Factor 5 CO unt, CO 0.1, CO 0.2, CO 0.29, CO gly
Analysis of Variance
Source DF Adj SS Adj MS F-Value P-Value
Factor 4 2.925 0.73131 10.51 0.000
Error 33 2.296 0.06958
Total 37 5.221
Model Summary
S R-sq R-sq(adj) R-sq(pred)
0.263784 56.02% 50.69% 40.75%
Means
Factor N Mean StDev 95% CI
CO unt 9 3.2000 0.2363 (3.0211, 3.3789)
CO 0.1 10 3.0000 0.2178 (2.8303, 3.1697)
CO 0.2 5 3.7360 0.1865 (3.4960, 3.9760)
CO 0.29 8 3.1375 0.2623 (2.9478, 3.3272)
CO gly 6 3.663 0.401 ( 3.444, 3.882)
Pooled StDev = 0.263784
Tukey Pairwise Comparisons
Grouping Information Using the Tukey Method and 95% Confidence
Factor N Mean Grouping
CO 0.2 5 3.7360 A
CO gly 6 3.663 A
CO unt 9 3.2000 B
CO 0.29 8 3.1375 B
CO 0.1 10 3.0000 B
Means that do not share a letter are significantly different.
Tukey Simultaneous Tests for Differences of Means
Difference SE of
Adjusted
Difference of Levels of Means Difference 95% CI T-Value P-
Value
CO 0.1 - CO unt -0.200 0.121 (-0.550, 0.150) -1.65 0.477
CO 0.2 - CO unt 0.536 0.147 ( 0.112, 0.960) 3.64 0.008
CO 0.29 - CO unt -0.063 0.128 (-0.432, 0.307) -0.49 0.988
CO gly - CO unt 0.463 0.139 ( 0.062, 0.864) 3.33 0.017
CO 0.2 - CO 0.1 0.736 0.144 ( 0.319, 1.153) 5.09 0.000
CO 0.29 - CO 0.1 0.137 0.125 (-0.223, 0.498) 1.10 0.806
CO gly - CO 0.1 0.663 0.136 ( 0.270, 1.056) 4.87 0.000
CO 0.29 - CO 0.2 -0.599 0.150 (-1.032, -0.165) -3.98 0.003
CO gly - CO 0.2 -0.073 0.160 (-0.533, 0.388) -0.45 0.991
75
CO gly - CO 0.29 0.526 0.142 ( 0.115, 0.937) 3.69 0.007
Individual confidence level = 99.32%
One-way ANOVA: Pull-out test cotton all samples including samples where
the yarn broke before it was pulled out.
Method
Null hypothesis All means are equal
Alternative hypothesis At least one mean is different
Significance level α = 0.05
Equal variances were assumed for the analysis.
Factor Information
Factor Levels Values
Factor 5 CO unt, CO 01, CO 0.2, CO 0.29, CO gly
Analysis of Variance
Source DF Adj SS Adj MS F-Value P-Value
Factor 4 4.445 1.11117 13.82 0.000
Error 45 3.617 0.08038
Total 49 8.062
Model Summary
S R-sq R-sq(adj) R-sq(pred)
0.283507 55.13% 51.15% 44.61%
Means
Factor N Mean StDev 95% CI
CO unt 10 3.2460 0.2660 (3.0654, 3.4266)
CO 01 10 3.0000 0.2178 (2.8194, 3.1806)
CO 0.2 10 3.8520 0.2573 (3.6714, 4.0326)
CO 0.29 10 3.238 0.332 ( 3.057, 3.419)
CO gly 10 3.578 0.328 ( 3.397, 3.759)
Pooled StDev = 0.283507
Tukey Pairwise Comparisons
Grouping Information Using the Tukey Method and 95% Confidence
Factor N Mean Grouping
CO 0.2 10 3.8520 A
CO gly 10 3.578 A B
CO unt 10 3.2460 B C
CO 0.29 10 3.238 B C
CO 01 10 3.0000 C
Means that do not share a letter are significantly different.
Tukey Simultaneous Tests for Differences of Means
Difference of Difference SE of Adjusted
Levels of Means Difference 95% CI T-Value P-Value
CO 01 - CO unt -0.246 0.127 (-0.606, 0.114) -1.94 0.312
CO 0.2 - CO unt 0.606 0.127 ( 0.246, 0.966) 4.78 0.000
CO 0.29 - CO unt -0.008 0.127 (-0.368, 0.352) -0.06 1.000
CO gly - CO unt 0.332 0.127 (-0.028, 0.692) 2.62 0.084
CO 0.2 - CO 01 0.852 0.127 ( 0.492, 1.212) 6.72 0.000
CO 0.29 - CO 01 0.238 0.127 (-0.122, 0.598) 1.88 0.344
CO gly - CO 01 0.578 0.127 ( 0.218, 0.938) 4.56 0.000
76
CO 0.29 - CO 0.2 -0.614 0.127 (-0.974, -0.254) -4.84 0.000
CO gly - CO 0.2 -0.274 0.127 (-0.634, 0.086) -2.16 0.213
CO gly - CO 0.29 0.340 0.127 (-0.020, 0.700) 2.68 0.073
Individual confidence level = 99.33%
One-way ANOVA: Pull-out test polyester
Method
Null hypothesis All means are equal
Alternative hypothesis At least one mean is different
Significance level α = 0.05
Equal variances were assumed for the analysis.
Factor Information
Factor Levels Values
Factor 5 PET unt, PET 0.1, PET 0.2, PET 0.71, PET gly
Analysis of Variance
Source DF Adj SS Adj MS F-Value P-Value
Factor 4 13.24 3.3093 5.14 0.002
Error 45 28.96 0.6437
Total 49 42.20
Model Summary
S R-sq R-sq(adj) R-sq(pred)
0.802281 31.37% 25.27% 15.27%
Means
Factor N Mean StDev 95% CI
PET unt 10 5.123 0.483 ( 4.612, 5.634)
PET 0.1 10 4.3030 0.3067 (3.7920, 4.8140)
PET 0.2 10 4.0140 0.3079 (3.5030, 4.5250)
PET 0.71 10 3.581 0.770 ( 3.070, 4.092)
PET gly 10 4.519 1.485 ( 4.008, 5.030)
Pooled StDev = 0.802281
Tukey Pairwise Comparisons
Grouping Information Using the Tukey Method and 95% Confidence
Factor N Mean Grouping
PET unt 10 5.123 A
PET gly 10 4.519 A B
PET 0.1 10 4.3030 A B
PET 0.2 10 4.0140 B
PET 0.71 10 3.581 B
Means that do not share a letter are significantly different.
Tukey Simultaneous Tests for Differences of Means
Difference Difference SE of Adjusted
of Levels of Means Difference 95% CI T-Value P-Value
PET 0.1 - PET unt -0.820 0.359 (-1.840, 0.200) -2.29 0.169
PET 0.2 - PET unt -1.109 0.359 (-2.129, -0.089) -3.09 0.027
PET 0.71 - PET unt -1.542 0.359 (-2.562, -0.522) -4.30 0.001
PET gly - PET unt -0.604 0.359 (-1.624, 0.416) -1.68 0.454
PET 0.2 - PET 0.1 -0.289 0.359 (-1.309, 0.731) -0.81 0.928
PET 0.71 - PET 0.1 -0.722 0.359 (-1.742, 0.298) -2.01 0.277
PET gly - PET 0.1 0.216 0.359 (-0.804, 1.236) 0.60 0.974
PET 0.71 - PET 0.2 -0.433 0.359 (-1.453, 0.587) -1.21 0.747
PET gly - PET 0.2 0.505 0.359 (-0.515, 1.525) 1.41 0.626
PET gly - PET 0.71 0.938 0.359 (-0.082, 1.958) 2.61 0.085
Individual confidence level = 99.33%
One-way ANOVA: Pull-out test polycotton all samples including samples
where the yarn broke before it was pulled out.
Method
77
Null hypothesis All means are equal
Alternative hypothesis At least one mean is different
Significance level α = 0.05
Equal variances were assumed for the analysis.
Factor Information
Factor Levels Values
Factor 5 COPES unt, COPES 0.1, COPES 0.2, COPES 0.5, COPES gly
Analysis of Variance
Source DF Adj SS Adj MS F-Value P-Value
Factor 4 13.75 3.4383 11.38 0.000
Error 45 13.59 0.3021
Total 49 27.35
Model Summary
S R-sq R-sq(adj) R-sq(pred)
0.549622 50.29% 45.87% 38.63%
Means
Factor N Mean StDev 95% CI
COPES unt 10 4.116 0.378 ( 3.766, 4.466)
COPES 0.1 10 4.393 0.483 ( 4.043, 4.743)
COPES 0.2 10 5.627 0.726 ( 5.277, 5.977)
COPES 0.5 10 4.842 0.737 ( 4.492, 5.192)
COPES gly 10 4.4520 0.2514 (4.1019, 4.8021)
Pooled StDev = 0.549622
Tukey Pairwise Comparisons
Grouping Information Using the Tukey Method and 95% Confidence
Factor N Mean Grouping
COPES 0.2 10 5.627 A
COPES 0.5 10 4.842 B
COPES gly 10 4.4520 B C
COPES 0.1 10 4.393 B C
COPES unt 10 4.116 C
Means that do not share a letter are significantly different.
Tukey Simultaneous Tests for Differences of Means
Difference of Difference SE of Adjusted
Levels of Means Difference 95% CI T-Value P-Value
COPES 0.1 - COPES unt 0.277 0.246 (-0.422, 0.976) 1.13 0.792
COPES 0.2 - COPES unt 1.511 0.246 ( 0.812, 2.210) 6.15 0.000
COPES 0.5 - COPES unt 0.726 0.246 ( 0.027, 1.425) 2.95 0.038
COPES gly - COPES unt 0.336 0.246 (-0.363, 1.035) 1.37 0.651
COPES 0.2 - COPES 0.1 1.234 0.246 ( 0.535, 1.933) 5.02 0.000
COPES 0.5 - COPES 0.1 0.449 0.246 (-0.250, 1.148) 1.83 0.371
COPES gly - COPES 0.1 0.059 0.246 (-0.640, 0.758) 0.24 0.999
COPES 0.5 - COPES 0.2 -0.785 0.246 (-1.484, -0.086) -3.19 0.021
COPES gly - COPES 0.2 -1.175 0.246 (-1.874, -0.476) -4.78 0.000
COPES gly - COPES 0.5 -0.390 0.246 (-1.089, 0.309) -1.59 0.513
Individual confidence level = 99.33%
78
APPENDIX IV: ANOVA FOR ROTOR SPUN YARN
One-way ANOVA: Rotor spun yarns Method
Null hypothesis All means are equal
Alternative hypothesis At least one mean is different
Significance level α = 0.05
Equal variances were assumed for the analysis.
Factor Information
Factor Levels Values
Factor 10 CO UNT, CO 0.1, CO 0.29, 8g CO UNT+ 8g vCO, 9g CO 0.1+ 9g
vCO, PES 0.2, PES
0.71, 9g PES 0.2+ 9g vCO, 9g PES 0.71+ 9g vCO, COTTON REF
Analysis of Variance
Source DF Adj SS Adj MS F-Value P-Value
Factor 9 598.8 66.531 20.54 0.000
Error 190 615.3 3.238
Total 199 1214.1
Model Summary
S R-sq R-sq(adj) R-sq(pred)
1.79956 49.32% 46.92% 43.84%
Means
Factor N Mean StDev 95% CI
CO UNT 20 7.400 1.188 ( 6.606, 8.194)
CO 0.1 20 7.350 0.933 ( 6.556, 8.144)
CO 0.29 20 6.300 1.750 ( 5.506, 7.094)
8g CO UNT+ 8g vCO 20 6.950 1.572 ( 6.156, 7.744)
9g CO 0.1+ 9g vCO 20 7.200 1.989 ( 6.406, 7.994)
PES 0.2 20 5.900 1.619 ( 5.106, 6.694)
PES 0.71 20 8.150 1.599 ( 7.356, 8.944)
9g PES 0.2+ 9g vCO 20 8.250 1.164 ( 7.456, 9.044)
9g PES 0.71+ 9g vCO 20 8.650 2.007 ( 7.856, 9.444)
COTTON REF 20 12.450 3.170 (11.656, 13.244)
Pooled StDev = 1.79956
Tukey Pairwise Comparisons
Grouping Information Using the Tukey Method and 95% Confidence
Factor N Mean Grouping
COTTON REF 20 12.450 A
9g PES 0.71+ 9g vCO 20 8.650 B
9g PES 0.2+ 9g vCO 20 8.250 B
PES 0.71 20 8.150 B
CO UNT 20 7.400 B C
CO 0.1 20 7.350 B C
9g CO 0.1+ 9g vCO 20 7.200 B C
8g CO UNT+ 8g vCO 20 6.950 B C
CO 0.29 20 6.300 C
PES 0.2 20 5.900 C
Means that do not share a letter are significantly different.
Tukey Simultaneous Tests for Differences of Means
Difference of Difference SE of Adjusted
79
Levels of Means Difference 95% CI T-Value P-Value
CO 0.1 - CO UNT -0.050 0.569 (-1.873, 1.773) -0.09 1.000
CO 0.29 - CO UNT -1.100 0.569 (-2.923, 0.723) -1.93 0.647
8g CO UNT+ 8 - CO UNT -0.450 0.569 (-2.273, 1.373) -0.79 0.999
9g CO 0.1+ 9 - CO UNT -0.200 0.569 (-2.023, 1.623) -0.35 1.000
PES 0.2 - CO UNT -1.500 0.569 (-3.323, 0.323) -2.64 0.209
PES 0.71 - CO UNT 0.750 0.569 (-1.073, 2.573) 1.32 0.948
9g PES 0.2+ - CO UNT 0.850 0.569 (-0.973, 2.673) 1.49 0.893
9g PES 0.71+ - CO UNT 1.250 0.569 (-0.573, 3.073) 2.20 0.463
COTTON REF - CO UNT 5.050 0.569 ( 3.227, 6.873) 8.87 0.000
CO 0.29 - CO 0.1 -1.050 0.569 (-2.873, 0.773) -1.85 0.706
8g CO UNT+ 8 - CO 0.1 -0.400 0.569 (-2.223, 1.423) -0.70 0.999
9g CO 0.1+ 9 - CO 0.1 -0.150 0.569 (-1.973, 1.673) -0.26 1.000
PES 0.2 - CO 0.1 -1.450 0.569 (-3.273, 0.373) -2.55 0.250
PES 0.71 - CO 0.1 0.800 0.569 (-1.023, 2.623) 1.41 0.924
9g PES 0.2+ - CO 0.1 0.900 0.569 (-0.923, 2.723) 1.58 0.856
9g PES 0.71+ - CO 0.1 1.300 0.569 (-0.523, 3.123) 2.28 0.404
COTTON REF - CO 0.1 5.100 0.569 ( 3.277, 6.923) 8.96 0.000
8g CO UNT+ 8 - CO 0.29 0.650 0.569 (-1.173, 2.473) 1.14 0.980
9g CO 0.1+ 9 - CO 0.29 0.900 0.569 (-0.923, 2.723) 1.58 0.856
PES 0.2 - CO 0.29 -0.400 0.569 (-2.223, 1.423) -0.70 0.999
PES 0.71 - CO 0.29 1.850 0.569 ( 0.027, 3.673) 3.25 0.043
9g PES 0.2+ - CO 0.29 1.950 0.569 ( 0.127, 3.773) 3.43 0.025
9g PES 0.71+ - CO 0.29 2.350 0.569 ( 0.527, 4.173) 4.13 0.002
COTTON REF - CO 0.29 6.150 0.569 ( 4.327, 7.973) 10.81 0.000
9g CO 0.1+ 9 - 8g CO UNT+ 8 0.250 0.569 (-1.573, 2.073) 0.44 1.000
PES 0.2 - 8g CO UNT+ 8 -1.050 0.569 (-2.873, 0.773) -1.85 0.706
PES 0.71 - 8g CO UNT+ 8 1.200 0.569 (-0.623, 3.023) 2.11 0.524
9g PES 0.2+ - 8g CO UNT+ 8 1.300 0.569 (-0.523, 3.123) 2.28 0.404
9g PES 0.71+ - 8g CO UNT+ 8 1.700 0.569 (-0.123, 3.523) 2.99 0.090
COTTON REF - 8g CO UNT+ 8 5.500 0.569 ( 3.677, 7.323) 9.66 0.000
PES 0.2 - 9g CO 0.1+ 9 -1.300 0.569 (-3.123, 0.523) -2.28 0.404
PES 0.71 - 9g CO 0.1+ 9 0.950 0.569 (-0.873, 2.773) 1.67 0.811
9g PES 0.2+ - 9g CO 0.1+ 9 1.050 0.569 (-0.773, 2.873) 1.85 0.706
9g PES 0.71+ - 9g CO 0.1+ 9 1.450 0.569 (-0.373, 3.273) 2.55 0.250
COTTON REF - 9g CO 0.1+ 9 5.250 0.569 ( 3.427, 7.073) 9.23 0.000
PES 0.71 - PES 0.2 2.250 0.569 ( 0.427, 4.073) 3.95 0.004
9g PES 0.2+ - PES 0.2 2.350 0.569 ( 0.527, 4.173) 4.13 0.002
9g PES 0.71+ - PES 0.2 2.750 0.569 ( 0.927, 4.573) 4.83 0.000
COTTON REF - PES 0.2 6.550 0.569 ( 4.727, 8.373) 11.51 0.000
9g PES 0.2+ - PES 0.71 0.100 0.569 (-1.723, 1.923) 0.18 1.000
9g PES 0.71+ - PES 0.71 0.500 0.569 (-1.323, 2.323) 0.88 0.997
COTTON REF - PES 0.71 4.300 0.569 ( 2.477, 6.123) 7.56 0.000
9g PES 0.71+ - 9g PES 0.2+ 0.400 0.569 (-1.423, 2.223) 0.70 0.999
COTTON REF - 9g PES 0.2+ 4.200 0.569 ( 2.377, 6.023) 7.38 0.000
COTTON REF - 9g PES 0.71+ 3.800 0.569 ( 1.977, 5.623) 6.68 0.000
Individual confidence level = 99.84%
80
APPENDIX V: ANOVA FOR ROTOR YARN AND
WASHED ROTOR YARNS One-way ANOVA: Rotor spun yarns and washed rotor spun yarns
Method
Null hypothesis All means are equal
Alternative hypothesis At least one mean is different
Significance level α = 0.05
Equal variances were assumed for the analysis.
Factor Information
Factor Levels Values
Factor 18 CO UNT, CO 0.1, CO 0.29, 8g CO UNT+ 8g vCO, 9g CO 0.1 + 9g
vCO, PET 0.71, 9g PET 0.2 + 9g vCO, 9g PET 0.71 + 9g vC, virgin CO ref., WY
CO UNT, WY CO 0.1, WY CO 0.29, WY 8g CO UNT+ 8g vCO, WY 9g CO 0.1 + 9g vCO,
WY PET 0.71, WY 9g PET 0.2 + 9g vCO, WY 9g PET 0.71 + 9g vCO, WY virgin CO
ref.
Analysis of Variance
Source DF Adj SS Adj MS F-Value P-Value
Factor 17 954.8 56.166 26.24 0.000
Error 342 732.1 2.141
Total 359 1687.0
Model Summary
S R-sq R-sq(adj) R-sq(pred)
1.46314 56.60% 54.44% 51.91%
Means
Factor N Mean StDev 95% CI
CO UNT 20 7.400 1.188 ( 6.756, 8.044)
CO 0.1 20 7.350 0.933 ( 6.706, 7.994)
CO 0.29 20 6.300 1.750 ( 5.656, 6.944)
8g CO UNT+ 8g vCO 20 6.950 1.572 ( 6.306, 7.594)
9g CO 0.1 + 9g vCO 20 7.200 1.989 ( 6.556, 7.844)
PET 0.71 20 8.150 1.599 ( 7.506, 8.794)
9g PET 0.2 + 9g vCO 20 8.250 1.164 ( 7.606, 8.894)
9g PET 0.71 + 9g vC 20 8.650 2.007 ( 8.006, 9.294)
virgin CO ref. 20 12.450 3.170 (11.806, 13.094)
WY CO UNT 20 7.700 1.261 ( 7.056, 8.344)
WY CO 0.1 20 8.500 1.395 ( 7.856, 9.144)
WY CO 0.29 20 9.050 0.999 ( 8.406, 9.694)
WY 8g CO UNT+ 8g vCO 20 7.350 0.933 ( 6.706, 7.994)
WY 9g CO 0.1 + 9g vCO 20 6.700 1.081 ( 6.056, 7.344)
WY PET 0.71 20 9.600 0.821 ( 8.956, 10.244)
WY 9g PET 0.2 + 9g vCO 20 8.600 0.681 ( 7.956, 9.244)
WY 9g PET 0.71 + 9g vCO 20 8.950 0.686 ( 8.306, 9.594)
WY virgin CO ref. 20 12.200 0.768 (11.556, 12.844)
Pooled StDev = 1.46314
Tukey Pairwise Comparisons Grouping Information Using the Tukey Method and 95% Confidence
Factor N Mean Grouping
virgin CO ref. 20 12.450 A
WY virgin CO ref. 20 12.200 A
WY PET 0.71 20 9.600 B
WY CO 0.29 20 9.050 B C
WY 9g PET 0.71 + 9g vCO 20 8.950 B C D
9g PET 0.71 + 9g vC 20 8.650 B C D E
WY 9g PET 0.2 + 9g vCO 20 8.600 B C D E
WY CO 0.1 20 8.500 B C D E F
9g PET 0.2 + 9g vCO 20 8.250 B C D E F G
PET 0.71 20 8.150 B C D E F G
WY CO UNT 20 7.700 C D E F G H
CO UNT 20 7.400 D E F G H
WY 8g CO UNT+ 8g vCO 20 7.350 D E F G H
CO 0.1 20 7.350 D E F G H
9g CO 0.1 + 9g vCO 20 7.200 E F G H
8g CO UNT+ 8g vCO 20 6.950 F G H
WY 9g CO 0.1 + 9g vCO 20 6.700 G H
81
CO 0.29 20 6.300 H
Means that do not share a letter are significantly different.
Tukey Simultaneous Tests for Differences of Means
Difference Difference SE of Adjusted
of Levels of Means Difference 95% CI T-Value P-Value
WY CO 0.29 - CO UNT 1.650 0.463 ( 0.037, 3.263) 3.57 0.039
WY PET 0.71 - CO UNT 2.200 0.463 ( 0.587, 3.813) 4.75 0.000
WY CO 0.29 - CO 0.1 1.700 0.463 ( 0.087, 3.313) 3.67 0.027
PET 0.71 - CO 0.29 1.850 0.463 ( 0.237, 3.463) 4.00 0.008
9g PET 0.2 + - CO 0.29 1.950 0.463 ( 0.337, 3.563) 4.21 0.003
9g PET 0.71 - CO 0.29 2.350 0.463 ( 0.737, 3.963) 5.08 0.000
WY CO 0.1 - CO 0.29 2.200 0.463 ( 0.587, 3.813) 4.75 0.000
WY CO 0.29 - CO 0.29 2.750 0.463 ( 1.137, 4.363) 5.94 0.000
WY PET 0.71 - CO 0.29 3.300 0.463 ( 1.687, 4.913) 7.13 0.000
WY 9g PET 0. - CO 0.29 2.300 0.463 ( 0.687, 3.913) 4.97 0.000
WY 9g PET 0. - CO 0.29 2.650 0.463 ( 1.037, 4.263) 5.73 0.000
9g PET 0.71 - 8g CO UNT+ 8 1.700 0.463 ( 0.087, 3.313) 3.67 0.027
WY CO 0.29 - 8g CO UNT+ 8 2.100 0.463 ( 0.487, 3.713) 4.54 0.001
WY PET 0.71 - 8g CO UNT+ 8 2.650 0.463 ( 1.037, 4.263) 5.73 0.000
WY 9g PET 0. - 8g CO UNT+ 8 1.650 0.463 ( 0.037, 3.263) 3.57 0.039
WY 9g PET 0. - 8g CO UNT+ 8 2.000 0.463 ( 0.387, 3.613) 4.32 0.002
WY CO 0.29 - 9g CO 0.1 + 1.850 0.463 ( 0.237, 3.463) 4.00 0.008
WY PET 0.71 - 9g CO 0.1 + 2.400 0.463 ( 0.787, 4.013) 5.19 0.000
WY 9g PET 0. - 9g CO 0.1 + 1.750 0.463 ( 0.137, 3.363) 3.78 0.018
WY 9g CO 0.1 - 9g PET 0.71 -1.950 0.463 (-3.563, -0.337) -4.21 0.003
WY PET 0.71 - WY CO UNT 1.900 0.463 ( 0.287, 3.513) 4.11 0.005
WY 9g CO 0.1 - WY CO 0.1 -1.800 0.463 (-3.413, -0.187) -3.89 0.012
WY 8g CO UNT - WY CO 0.29 -1.700 0.463 (-3.313, -0.087) -3.67 0.027
WY 9g CO 0.1 - WY CO 0.29 -2.350 0.463 (-3.963, -0.737) -5.08 0.000
WY PET 0.71 - WY 8g CO UNT 2.250 0.463 ( 0.637, 3.863) 4.86 0.000
WY PET 0.71 - WY 9g CO 0.1 2.900 0.463 ( 1.287, 4.513) 6.27 0.000
WY 9g PET 0. - WY 9g CO 0.1 1.900 0.463 ( 0.287, 3.513) 4.11 0.005
WY 9g PET 0. - WY 9g CO 0.1 2.250 0.463 ( 0.637, 3.863) 4.86 0.000
Individual confidence level = 99.94%
82
APPENDIX VI: RESULTS Table 21. Calculations for concentrations.
Sample weight
fabric (g)
Water
uptake
10% bath
volume
w%
PEG
4000
PEG
4000 (g)
PET/CO 3500 0.68 1.1 2618 0.001 3.85
CO 3500 0.82 1.1 3157 0.001 3.85
PET 3850 0.82 1.1 3472.7 0.002 8.47
Sample weight
fabric (g)
Water
uptake
20% bath
volume
w%
PEG
4000
PEG
4000 (g)
PET
0.15w%
109.19 0.82 1.2 107.443 0.0015 0.196542
PET
0.1w%
107.71 0.82 1.2 105.9866 0.001 0.129252
CO
0.2w%
131.79 0.82 1.2 129.6814 0.002 0.316296
CO
0.15w%
133.11 0.82 1.2 130.9802 0.0015 0.239598
PET/CO
0.2w%
120.38 0.68 1.2 98.23008 0.002 0.288912
PET/CO
0.15w%
97.95 0.68 1.2 79.9272 0.0015 0.17631
Table 22. Pull-out for cotton samples. For samples marked with grey the yarn broke
before it was pulled out, meaning that the pull-out force were higher than the tensile
strength of the yarn.
Sample Force [N]
CO unt 3.36 3.43 2.99 3.53 3.06 3.05 2.96 2.97 3.45 3.66 CO 01 w%
PEG 4000 2.93 3.1 3.16 2.74 3.26 3.23 2.58 3.07 3.05 2.88 CO 0.2 w%
PEG 4000 3.75 3.68 3.91 3.89 3.45 4.11 3.57 4.22 3.77 4.17 CO 0.29 w%
PEG 4000 3.37 3.42 2.93 2.73 3.36 3.21 2.86 3.22 3.41 3.87
CO gly 3.41 3.36 4.35 3.92 3.6 3.34 3.31 3.36 3.58 3.55
Table 23. Pull-out for polycotton samples. For samples marked with grey the yarn broke
before it was pulled out, meaning that the pull-out force were higher than the tensile
strength of the yarn.
Sample Force [N]
COPES unt 4.17 4.32 3.47 4.11 3.98 4.1 3.86 3.91 4.93 4.31
COPES 0.1
w% PEG 4000 4.33 3.82 4.49 4.42 4.26 4.82 4.34 3.48 5.09 4.88
83
COPES 0.2
w% PEG 4000 5.33 6.46 5.03 5.87 5.5 5.23 5.04 6.92 4.64 6.25
COPES 0.5
w% PEG 4000 5.37 5.02 4.54 5.78 5.92 4.79 4.41 5.01 3.86 3.72
COPES gly 4.77 4.37 4.1 4.63 4.48 4.15 4.22 4.72 4.35 4.73
Table 24. Sprockets tested to alter the drawing.
A B C D
1 20 22 20 22
2 20 22 34 20
3 20 22 20 34
4 20 24 20 42
5 20 24 42 20
6 20 24 20 46
7 24 20 52 20
8 32 20 52 20
84
APPENDIX VII: RAMAN SPECTROSCOPY
Figure 28.Raman spectroscopy, the blue curve is polyethylene terephthalate fibres from
the untreated shredded fabrics and the red curve is the Bicomponent PET.
85
APPENDIX VIII: PICTURES OF SAMPLES FOR
FIBRE LENGTH MEASUREMENT
Figure 29. Fibre length measurement for cotton fabric, weft and warp, and virgin cotton
fibres.
86
Figure 30. Fibre length measurement for polyester fabric weft and for polycotton fabric,
both weft and warp.
90
APPENDIX IX: PICTURES OF SAMPLES FOR NEPS
AND UMOPENED THREADS ANALYSIS
Figure 34. Neps and unopened threads in shredded samples of cotton. Treatment; a)
glycerol b) 0.29 w% PEG 4000 c) 0.1 w% PEG 4000 d) untreated.
91
Figure 35. Neps and unopened threads in shredded samples of polyester. Treatment; a)
glycerol b) 0.71w% PEG 4000 c) 0.2 w% PEG 4000 d) untreated
92
Figure 36. Neps and unopened threads in shredded samples of polycotton. Treatment; a)
glycerol b) 0.5 w% PEG 4000 c) 0.1 w% PEG 4000 d) untreated
93
APPENDIX X: PICTURES OF ROTOR SPUN YARN Table 25. Pictures of rotor spun yarns.
Sample
CO unt
CO 0.1 w% PEG
4000
CO 0.29 w%
PEG 4000
95
PET 0.71 w%
PEG 4000
9 g PET 0.2 w%
PEG 4000 + 9 g
virgin CO
9 g PET 0.71
w% PEG 4000 +
9 g virgin CO
97
APPENDIX XI. CUTTER AND SHREDDING
MACHINE. Model NSX-QD350 (cutting machine)
Producer Qing Dao New Shunxing Environmental Protection and
Technology Co
Capacity 1000-1500 kg/h
Rotary blades
(diameter)
320 mm
Speed (rotary blades) 230 turns/min
Cut size 5-250 mm
Voltage 380 V (50 hz)
Conveyor belt 380 x 4000 x 3 mm
Machine size 3550 x 960 x 1200 mm
Weight ~800 kg
Model NSX-FS1040
Producer Qing Dao New Shunxing Environmental Protection and
Technology Co
Capacity 100-120 kg/h
Cylinder (diameter) 400 mm
Speed (cylinder) 1350 turns/min
Needle gauge 4.5/25.4 needles/ mm
Engine 1.5 kw
Fan 1.1 kw
Machine size 2100 x 1450 x 1550 mm
Model NSX-QT310
Producer Qing Dao New Shunxing Environmental Protection and
Technology Co
Capacity 100-120 kg/ h
Cylinder (diameter) 250 mm
Speed (cylinder 1) 1900 turns/ min
Speed (cylinder 2 & 3) 2000 turns /min
Needle gauge (cylinder
1)
4.5/25.4 needles/ mm
Needle gauge (cylinder
2 & 3)
6/25.4 needles/ mm
Engine 5.5 kw
Fan 1.1 kw
Machine size 4610 x 1720 x 1160 mm
Weigh 1600 kg